From 525823a7548d73c9ec9ba3ae84663ab286b20205 Mon Sep 17 00:00:00 2001
From: alanv <alanv@google.com>
Date: Wed, 16 May 2012 20:01:51 -0700
Subject: [PATCH] Refactor WebView accessibility code into a separate class.

Bug: 5932640
Change-Id: I52ab57f51c5904cbcf56307f17f406b2a30d6b91
---
 .../android/webkit/AccessibilityInjector.java | 683 +++++++-----------
 .../webkit/AccessibilityInjectorFallback.java | 499 +++++++++++++
 core/java/android/webkit/WebViewClassic.java  | 282 +-------
 3 files changed, 806 insertions(+), 658 deletions(-)
 create mode 100644 core/java/android/webkit/AccessibilityInjectorFallback.java

diff --git a/core/java/android/webkit/AccessibilityInjector.java b/core/java/android/webkit/AccessibilityInjector.java
index 11bd815c685d5..915e2dc22fb06 100644
--- a/core/java/android/webkit/AccessibilityInjector.java
+++ b/core/java/android/webkit/AccessibilityInjector.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010 The Android Open Source Project
+ * Copyright (C) 2012 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,484 +16,335 @@
 
 package android.webkit;
 
+import android.content.Context;
+import android.os.Vibrator;
 import android.provider.Settings;
-import android.text.TextUtils;
-import android.text.TextUtils.SimpleStringSplitter;
-import android.util.Log;
+import android.speech.tts.TextToSpeech;
 import android.view.KeyEvent;
-import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityManager;
 import android.webkit.WebViewCore.EventHub;
 
-import java.util.ArrayList;
-import java.util.Stack;
+import org.apache.http.NameValuePair;
+import org.apache.http.client.utils.URLEncodedUtils;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.List;
 
 /**
- * This class injects accessibility into WebViews with disabled JavaScript or
- * WebViews with enabled JavaScript but for which we have no accessibility
- * script to inject.
- * </p>
- * Note: To avoid changes in the framework upon changing the available
- *       navigation axis, or reordering the navigation axis, or changing
- *       the key bindings, or defining sequence of actions to be bound to
- *       a given key this class is navigation axis agnostic. It is only
- *       aware of one navigation axis which is in fact the default behavior
- *       of webViews while using the DPAD/TrackBall.
- * </p>
- * In general a key binding is a mapping from modifiers + key code to
- * a sequence of actions. For more detail how to specify key bindings refer to
- * {@link android.provider.Settings.Secure#ACCESSIBILITY_WEB_CONTENT_KEY_BINDINGS}.
- * </p>
- * The possible actions are invocations to
- * {@link #setCurrentAxis(int, boolean, String)}, or
- * {@link #traverseCurrentAxis(int, boolean, String)}
- * {@link #traverseGivenAxis(int, int, boolean, String)}
- * {@link #prefromAxisTransition(int, int, boolean, String)}
- * referred via the values of:
- * {@link #ACTION_SET_CURRENT_AXIS},
- * {@link #ACTION_TRAVERSE_CURRENT_AXIS},
- * {@link #ACTION_TRAVERSE_GIVEN_AXIS},
- * {@link #ACTION_PERFORM_AXIS_TRANSITION},
- * respectively.
- * The arguments for the action invocation are specified as offset
- * hexademical pairs. Note the last argument of the invocation
- * should NOT be specified in the binding as it is provided by
- * this class. For details about the key binding implementation
- * refer to {@link AccessibilityWebContentKeyBinding}.
+ * Handles injecting accessibility JavaScript and related JavaScript -> Java
+ * APIs.
  */
 class AccessibilityInjector {
-    private static final String LOG_TAG = "AccessibilityInjector";
+    // The WebViewClassic this injector is responsible for managing.
+    private final WebViewClassic mWebViewClassic;
 
-    private static final boolean DEBUG = true;
+    // Cached reference to mWebViewClassic.getContext(), for convenience.
+    private final Context mContext;
 
-    private static final int ACTION_SET_CURRENT_AXIS = 0;
-    private static final int ACTION_TRAVERSE_CURRENT_AXIS = 1;
-    private static final int ACTION_TRAVERSE_GIVEN_AXIS = 2;
-    private static final int ACTION_PERFORM_AXIS_TRANSITION = 3;
-    private static final int ACTION_TRAVERSE_DEFAULT_WEB_VIEW_BEHAVIOR_AXIS = 4;
+    // Cached reference to mWebViewClassic.getWebView(), for convenience.
+    private final WebView mWebView;
 
-    // the default WebView behavior abstracted as a navigation axis
-    private static final int NAVIGATION_AXIS_DEFAULT_WEB_VIEW_BEHAVIOR = 7;
+    // The Java objects that are exposed to JavaScript.
+    private TextToSpeech mTextToSpeech;
 
-    // these are the same for all instances so make them process wide
-    private static ArrayList<AccessibilityWebContentKeyBinding> sBindings =
-        new ArrayList<AccessibilityWebContentKeyBinding>();
+    // Lazily loaded helper objects.
+    private AccessibilityManager mAccessibilityManager;
+    private AccessibilityInjectorFallback mAccessibilityInjector;
 
-    // handle to the WebViewClassic this injector is associated with.
-    private final WebViewClassic mWebView;
+    // Whether the accessibility script has been injected into the current page.
+    private boolean mAccessibilityScriptInjected;
 
-    // events scheduled for sending as soon as we receive the selected text
-    private final Stack<AccessibilityEvent> mScheduledEventStack = new Stack<AccessibilityEvent>();
+    // Constants for determining script injection strategy.
+    private static final int ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED = -1;
+    private static final int ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT = 0;
+    @SuppressWarnings("unused")
+    private static final int ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED = 1;
 
-    // the current traversal axis
-    private int mCurrentAxis = 2; // sentence
+    // Aliases for Java objects exposed to JavaScript.
+    private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE = "accessibility";
 
-    // we need to consume the up if we have handled the last down
-    private boolean mLastDownEventHandled;
-
-    // getting two empty selection strings in a row we let the WebView handle the event
-    private boolean mIsLastSelectionStringNull;
-
-    // keep track of last direction
-    private int mLastDirection;
+    // Template for JavaScript that injects a screen-reader.
+    private static final String ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE =
+            "javascript:(function() {" +
+                    "    var chooser = document.createElement('script');" +
+                    "    chooser.type = 'text/javascript';" +
+                    "    chooser.src = '%1s';" +
+                    "    document.getElementsByTagName('head')[0].appendChild(chooser);" +
+                    "  })();";
 
     /**
-     * Creates a new injector associated with a given {@link WebViewClassic}.
+     * Creates an instance of the AccessibilityInjector based on
+     * {@code webViewClassic}.
      *
-     * @param webView The associated WebViewClassic.
+     * @param webViewClassic The WebViewClassic that this AccessibilityInjector
+     *            manages.
      */
-    public AccessibilityInjector(WebViewClassic webView) {
-        mWebView = webView;
-        ensureWebContentKeyBindings();
+    public AccessibilityInjector(WebViewClassic webViewClassic) {
+        mWebViewClassic = webViewClassic;
+        mWebView = webViewClassic.getWebView();
+        mContext = webViewClassic.getContext();
+        mAccessibilityManager = AccessibilityManager.getInstance(mContext);
     }
 
     /**
-     * Processes a key down <code>event</code>.
-     *
-     * @return True if the event was processed.
+     * Attempts to load scripting interfaces for accessibility.
+     * <p>
+     * This should be called when the window is attached.
+     * </p>
      */
-    public boolean onKeyEvent(KeyEvent event) {
-        // We do not handle ENTER in any circumstances.
-        if (isEnterActionKey(event.getKeyCode())) {
+    public void addAccessibilityApisIfNecessary() {
+        if (!isAccessibilityEnabled() || !isJavaScriptEnabled()) {
+            return;
+        }
+
+        addTtsApis();
+    }
+
+    /**
+     * Attempts to unload scripting interfaces for accessibility.
+     * <p>
+     * This should be called when the window is detached.
+     * </p>
+     */
+    public void removeAccessibilityApisIfNecessary() {
+        removeTtsApis();
+    }
+
+    /**
+     * Attempts to handle key events when accessibility is turned on.
+     *
+     * @param event The key event to handle.
+     * @return {@code true} if the event was handled.
+     */
+    public boolean handleKeyEventIfNecessary(KeyEvent event) {
+        if (!isAccessibilityEnabled()) {
+            mAccessibilityScriptInjected = false;
+            toggleFallbackAccessibilityInjector(false);
             return false;
         }
 
-        if (event.getAction() == KeyEvent.ACTION_UP) {
-            return mLastDownEventHandled;
-        }
-
-        mLastDownEventHandled = false;
-
-        AccessibilityWebContentKeyBinding binding = null;
-        for (AccessibilityWebContentKeyBinding candidate : sBindings) {
-            if (event.getKeyCode() == candidate.getKeyCode()
-                    && event.hasModifiers(candidate.getModifiers())) {
-                binding = candidate;
-                break;
+        if (mAccessibilityScriptInjected) {
+            // if an accessibility script is injected we delegate to it the key
+            // handling. this script is a screen reader which is a fully fledged
+            // solution for blind users to navigate in and interact with web
+            // pages.
+            if (event.getAction() == KeyEvent.ACTION_UP) {
+                mWebViewClassic.sendBatchableInputMessage(EventHub.KEY_UP, 0, 0, event);
+            } else if (event.getAction() == KeyEvent.ACTION_DOWN) {
+                mWebViewClassic.sendBatchableInputMessage(EventHub.KEY_DOWN, 0, 0, event);
+            } else {
+                return false;
             }
+
+            return true;
         }
 
-        if (binding == null) {
+        if (mAccessibilityInjector != null) {
+            // if an accessibility injector is present (no JavaScript enabled or
+            // the site opts out injecting our JavaScript screen reader) we let
+            // it decide whether to act on and consume the event.
+            return mAccessibilityInjector.onKeyEvent(event);
+        }
+
+        return false;
+    }
+
+    /**
+     * Attempts to handle selection change events when accessibility is using a
+     * non-JavaScript method.
+     *
+     * @param selectionString The selection string.
+     */
+    public void handleSelectionChangedIfNecessary(String selectionString) {
+        if (mAccessibilityInjector != null) {
+            mAccessibilityInjector.onSelectionStringChange(selectionString);
+        }
+    }
+
+    /**
+     * Prepares for injecting accessibility scripts into a new page.
+     *
+     * @param url The URL that will be loaded.
+     */
+    public void onPageStarted(String url) {
+        mAccessibilityScriptInjected = false;
+    }
+
+    /**
+     * Attempts to inject the accessibility script using a {@code <script>} tag.
+     * <p>
+     * This should be called after a page has finished loading.
+     * </p>
+     *
+     * @param url The URL that just finished loading.
+     */
+    public void onPageFinished(String url) {
+        if (!isAccessibilityEnabled()) {
+            mAccessibilityScriptInjected = false;
+            toggleFallbackAccessibilityInjector(false);
+            return;
+        }
+
+        if (!shouldInjectJavaScript(url)) {
+            toggleFallbackAccessibilityInjector(true);
+            return;
+        }
+
+        toggleFallbackAccessibilityInjector(false);
+
+        final String injectionUrl = getScreenReaderInjectionUrl();
+        mWebView.loadUrl(injectionUrl);
+
+        mAccessibilityScriptInjected = true;
+    }
+
+    /**
+     * Toggles the non-JavaScript method for handling accessibility.
+     *
+     * @param enabled {@code true} to enable the non-JavaScript method, or
+     *            {@code false} to disable it.
+     */
+    private void toggleFallbackAccessibilityInjector(boolean enabled) {
+        if (enabled && (mAccessibilityInjector == null)) {
+            mAccessibilityInjector = new AccessibilityInjectorFallback(mWebViewClassic);
+        } else {
+            mAccessibilityInjector = null;
+        }
+    }
+
+    /**
+     * Determines whether it's okay to inject JavaScript into a given URL.
+     *
+     * @param url The URL to check.
+     * @return {@code true} if JavaScript should be injected, {@code false} if a
+     *         non-JavaScript method should be used.
+     */
+    private boolean shouldInjectJavaScript(String url) {
+        // Respect the WebView's JavaScript setting.
+        if (!isJavaScriptEnabled()) {
             return false;
         }
 
-        for (int i = 0, count = binding.getActionCount(); i < count; i++) {
-            int actionCode = binding.getActionCode(i);
-            String contentDescription = Integer.toHexString(binding.getAction(i));
-            switch (actionCode) {
-                case ACTION_SET_CURRENT_AXIS:
-                    int axis = binding.getFirstArgument(i);
-                    boolean sendEvent = (binding.getSecondArgument(i) == 1);
-                    setCurrentAxis(axis, sendEvent, contentDescription);
-                    mLastDownEventHandled = true;
-                    break;
-                case ACTION_TRAVERSE_CURRENT_AXIS:
-                    int direction = binding.getFirstArgument(i);
-                    // on second null selection string in same direction - WebView handles the event
-                    if (direction == mLastDirection && mIsLastSelectionStringNull) {
-                        mIsLastSelectionStringNull = false;
-                        return false;
-                    }
-                    mLastDirection = direction;
-                    sendEvent = (binding.getSecondArgument(i) == 1);
-                    mLastDownEventHandled = traverseCurrentAxis(direction, sendEvent,
-                            contentDescription);
-                    break;
-                case ACTION_TRAVERSE_GIVEN_AXIS:
-                    direction = binding.getFirstArgument(i);
-                    // on second null selection string in same direction => WebView handle the event
-                    if (direction == mLastDirection && mIsLastSelectionStringNull) {
-                        mIsLastSelectionStringNull = false;
-                        return false;
-                    }
-                    mLastDirection = direction;
-                    axis =  binding.getSecondArgument(i);
-                    sendEvent = (binding.getThirdArgument(i) == 1);
-                    traverseGivenAxis(direction, axis, sendEvent, contentDescription);
-                    mLastDownEventHandled = true;
-                    break;
-                case ACTION_PERFORM_AXIS_TRANSITION:
-                    int fromAxis = binding.getFirstArgument(i);
-                    int toAxis = binding.getSecondArgument(i);
-                    sendEvent = (binding.getThirdArgument(i) == 1);
-                    prefromAxisTransition(fromAxis, toAxis, sendEvent, contentDescription);
-                    mLastDownEventHandled = true;
-                    break;
-                case ACTION_TRAVERSE_DEFAULT_WEB_VIEW_BEHAVIOR_AXIS:
-                    // This is a special case since we treat the default WebView navigation
-                    // behavior as one of the possible navigation axis the user can use.
-                    // If we are not on the default WebView navigation axis this is NOP.
-                    if (mCurrentAxis == NAVIGATION_AXIS_DEFAULT_WEB_VIEW_BEHAVIOR) {
-                        // While WebVew handles navigation we do not get null selection
-                        // strings so do not check for that here as the cases above.
-                        mLastDirection = binding.getFirstArgument(i);
-                        sendEvent = (binding.getSecondArgument(i) == 1);
-                        traverseGivenAxis(mLastDirection, NAVIGATION_AXIS_DEFAULT_WEB_VIEW_BEHAVIOR,
-                            sendEvent, contentDescription);
-                        mLastDownEventHandled = false;
-                    } else {
-                        mLastDownEventHandled = true;
-                    }
-                    break;
-                default:
-                    Log.w(LOG_TAG, "Unknown action code: " + actionCode);
-            }
-        }
-
-        return mLastDownEventHandled;
-    }
-
-    /**
-     * Set the current navigation axis which will be used while
-     * calling {@link #traverseCurrentAxis(int, boolean, String)}.
-     *
-     * @param axis The axis to set.
-     * @param sendEvent Whether to send an accessibility event to
-     *        announce the change.
-     */
-    private void setCurrentAxis(int axis, boolean sendEvent, String contentDescription) {
-        mCurrentAxis = axis;
-        if (sendEvent) {
-            AccessibilityEvent event = getPartialyPopulatedAccessibilityEvent();
-            event.getText().add(String.valueOf(axis));
-            event.setContentDescription(contentDescription);
-            sendAccessibilityEvent(event);
-        }
-    }
-
-    /**
-     * Performs conditional transition one axis to another.
-     *
-     * @param fromAxis The axis which must be the current for the transition to occur.
-     * @param toAxis The axis to which to transition.
-     * @param sendEvent Flag if to send an event to announce successful transition.
-     * @param contentDescription A description of the performed action.
-     */
-    private void prefromAxisTransition(int fromAxis, int toAxis, boolean sendEvent,
-            String contentDescription) {
-        if (mCurrentAxis == fromAxis) {
-            setCurrentAxis(toAxis, sendEvent, contentDescription);
-        }
-    }
-
-    /**
-     * Traverse the document along the current navigation axis.
-     *
-     * @param direction The direction of traversal.
-     * @param sendEvent Whether to send an accessibility event to
-     *        announce the change.
-     * @param contentDescription A description of the performed action.
-     * @see #setCurrentAxis(int, boolean, String)
-     */
-    private boolean traverseCurrentAxis(int direction, boolean sendEvent,
-            String contentDescription) {
-        return traverseGivenAxis(direction, mCurrentAxis, sendEvent, contentDescription);
-    }
-
-    /**
-     * Traverse the document along the given navigation axis.
-     *
-     * @param direction The direction of traversal.
-     * @param axis The axis along which to traverse.
-     * @param sendEvent Whether to send an accessibility event to
-     *        announce the change.
-     * @param contentDescription A description of the performed action.
-     */
-    private boolean traverseGivenAxis(int direction, int axis, boolean sendEvent,
-            String contentDescription) {
-        WebViewCore webViewCore = mWebView.getWebViewCore();
-        if (webViewCore == null) {
+        // Allow the page to opt out of Accessibility script injection.
+        if (getAxsUrlParameterValue(url) == ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT) {
             return false;
         }
 
-        AccessibilityEvent event = null;
-        if (sendEvent) {
-            event = getPartialyPopulatedAccessibilityEvent();
-            // the text will be set upon receiving the selection string
-            event.setContentDescription(contentDescription);
-        }
-        mScheduledEventStack.push(event);
-
-        // if the axis is the default let WebView handle the event which will
-        // result in cursor ring movement and selection of its content
-        if (axis == NAVIGATION_AXIS_DEFAULT_WEB_VIEW_BEHAVIOR) {
+        // The user must explicitly enable Accessibility script injection.
+        if (!isScriptInjectionEnabled()) {
             return false;
         }
 
-        webViewCore.sendMessage(EventHub.MODIFY_SELECTION, direction, axis);
         return true;
     }
 
     /**
-     * Called when the <code>selectionString</code> has changed.
+     * @return {@code true} if the user has explicitly enabled Accessibility
+     *         script injection.
      */
-    public void onSelectionStringChange(String selectionString) {
-        if (DEBUG) {
-            Log.d(LOG_TAG, "Selection string: " + selectionString);
-        }
-        mIsLastSelectionStringNull = (selectionString == null);
-        if (mScheduledEventStack.isEmpty()) {
-            return;
-        }
-        AccessibilityEvent event = mScheduledEventStack.pop();
-        if (event != null) {
-            event.getText().add(selectionString);
-            sendAccessibilityEvent(event);
-        }
+    private boolean isScriptInjectionEnabled() {
+        final int injectionSetting = Settings.Secure.getInt(
+                mContext.getContentResolver(), Settings.Secure.ACCESSIBILITY_SCRIPT_INJECTION, 0);
+        return (injectionSetting == 1);
     }
 
     /**
-     * Sends an {@link AccessibilityEvent}.
+     * Attempts to initialize and add interfaces for TTS, if that hasn't already
+     * been done.
+     */
+    private void addTtsApis() {
+        if (mTextToSpeech != null) {
+            return;
+        }
+
+        final String pkgName = mContext.getPackageName();
+
+        mTextToSpeech = new TextToSpeech(mContext, null, null, pkgName + ".**webview**", true);
+        mWebView.addJavascriptInterface(mTextToSpeech, ALIAS_ACCESSIBILITY_JS_INTERFACE);
+    }
+
+    /**
+     * Attempts to shutdown and remove interfaces for TTS, if that hasn't
+     * already been done.
+     */
+    private void removeTtsApis() {
+        if (mTextToSpeech == null) {
+            return;
+        }
+
+        mWebView.removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE);
+        mTextToSpeech.stop();
+        mTextToSpeech.shutdown();
+        mTextToSpeech = null;
+    }
+
+    /**
+     * Returns the script injection preference requested by the URL, or
+     * {@link #ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED} if the page has no
+     * preference.
      *
-     * @param event The event to send.
+     * @param url The URL to check.
+     * @return A script injection preference.
      */
-    private void sendAccessibilityEvent(AccessibilityEvent event) {
-        if (DEBUG) {
-            Log.d(LOG_TAG, "Dispatching: " + event);
-        }
-        // accessibility may be disabled while waiting for the selection string
-        AccessibilityManager accessibilityManager =
-            AccessibilityManager.getInstance(mWebView.getContext());
-        if (accessibilityManager.isEnabled()) {
-            accessibilityManager.sendAccessibilityEvent(event);
-        }
-    }
-
-    /**
-     * @return An accessibility event whose members are populated except its
-     *         text and content description.
-     */
-    private AccessibilityEvent getPartialyPopulatedAccessibilityEvent() {
-        AccessibilityEvent event = AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_SELECTED);
-        event.setClassName(mWebView.getClass().getName());
-        event.setPackageName(mWebView.getContext().getPackageName());
-        event.setEnabled(mWebView.getWebView().isEnabled());
-        return event;
-    }
-
-    /**
-     * Ensures that the Web content key bindings are loaded.
-     */
-    private void ensureWebContentKeyBindings() {
-        if (sBindings.size() > 0) {
-            return;
+    private int getAxsUrlParameterValue(String url) {
+        if (url == null) {
+            return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
         }
 
-        String webContentKeyBindingsString  = Settings.Secure.getString(
-                mWebView.getContext().getContentResolver(),
-                Settings.Secure.ACCESSIBILITY_WEB_CONTENT_KEY_BINDINGS);
+        try {
+            final List<NameValuePair> params = URLEncodedUtils.parse(new URI(url), null);
 
-        SimpleStringSplitter semiColonSplitter = new SimpleStringSplitter(';');
-        semiColonSplitter.setString(webContentKeyBindingsString);
-
-        while (semiColonSplitter.hasNext()) {
-            String bindingString = semiColonSplitter.next();
-            if (TextUtils.isEmpty(bindingString)) {
-                Log.e(LOG_TAG, "Disregarding malformed Web content key binding: "
-                        + webContentKeyBindingsString);
-                continue;
-            }
-            String[] keyValueArray = bindingString.split("=");
-            if (keyValueArray.length != 2) {
-                Log.e(LOG_TAG, "Disregarding malformed Web content key binding: " + bindingString);
-                continue;
-            }
-            try {
-                long keyCodeAndModifiers = Long.decode(keyValueArray[0].trim());
-                String[] actionStrings = keyValueArray[1].split(":");
-                int[] actions = new int[actionStrings.length];
-                for (int i = 0, count = actions.length; i < count; i++) {
-                    actions[i] = Integer.decode(actionStrings[i].trim());
+            for (NameValuePair param : params) {
+                if ("axs".equals(param.getName())) {
+                    return verifyInjectionValue(param.getValue());
                 }
-                sBindings.add(new AccessibilityWebContentKeyBinding(keyCodeAndModifiers, actions));
-            } catch (NumberFormatException nfe) {
-                Log.e(LOG_TAG, "Disregarding malformed key binding: " + bindingString);
             }
+        } catch (URISyntaxException e) {
+            // Do nothing.
         }
+
+        return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
     }
 
-    private boolean isEnterActionKey(int keyCode) {
-        return keyCode == KeyEvent.KEYCODE_DPAD_CENTER
-                || keyCode == KeyEvent.KEYCODE_ENTER
-                || keyCode == KeyEvent.KEYCODE_NUMPAD_ENTER;
+    private int verifyInjectionValue(String value) {
+        try {
+            final int parsed = Integer.parseInt(value);
+
+            switch (parsed) {
+                case ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT:
+                    return ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT;
+                case ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED:
+                    return ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED;
+            }
+        } catch (NumberFormatException e) {
+            // Do nothing.
+        }
+
+        return ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED;
     }
 
     /**
-     * Represents a web content key-binding.
+     * @return The URL for injecting the screen reader.
      */
-    private static final class AccessibilityWebContentKeyBinding {
+    private String getScreenReaderInjectionUrl() {
+        final String screenReaderUrl = Settings.Secure.getString(
+                mContext.getContentResolver(), Settings.Secure.ACCESSIBILITY_SCREEN_READER_URL);
+        return String.format(ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE, screenReaderUrl);
+    }
 
-        private static final int MODIFIERS_OFFSET = 32;
-        private static final long MODIFIERS_MASK = 0xFFFFFFF00000000L;
+    /**
+     * @return {@code true} if JavaScript is enabled in the {@link WebView}
+     *         settings.
+     */
+    private boolean isJavaScriptEnabled() {
+        return mWebView.getSettings().getJavaScriptEnabled();
+    }
 
-        private static final int KEY_CODE_OFFSET = 0;
-        private static final long KEY_CODE_MASK = 0x00000000FFFFFFFFL;
-
-        private static final int ACTION_OFFSET = 24;
-        private static final int ACTION_MASK = 0xFF000000;
-
-        private static final int FIRST_ARGUMENT_OFFSET = 16;
-        private static final int FIRST_ARGUMENT_MASK = 0x00FF0000;
-
-        private static final int SECOND_ARGUMENT_OFFSET = 8;
-        private static final int SECOND_ARGUMENT_MASK = 0x0000FF00;
-
-        private static final int THIRD_ARGUMENT_OFFSET = 0;
-        private static final int THIRD_ARGUMENT_MASK = 0x000000FF;
-
-        private final long mKeyCodeAndModifiers;
-
-        private final int [] mActionSequence;
-
-        /**
-         * @return The key code of the binding key.
-         */
-        public int getKeyCode() {
-            return (int) ((mKeyCodeAndModifiers & KEY_CODE_MASK) >> KEY_CODE_OFFSET);
-        }
-
-        /**
-         * @return The meta state of the binding key.
-         */
-        public int getModifiers() {
-            return (int) ((mKeyCodeAndModifiers & MODIFIERS_MASK) >> MODIFIERS_OFFSET);
-        }
-
-        /**
-         * @return The number of actions in the key binding.
-         */
-        public int getActionCount() {
-            return mActionSequence.length;
-        }
-
-        /**
-         * @param index The action for a given action <code>index</code>.
-         */
-        public int getAction(int index) {
-            return mActionSequence[index];
-        }
-
-        /**
-         * @param index The action code for a given action <code>index</code>.
-         */
-        public int getActionCode(int index) {
-            return (mActionSequence[index] & ACTION_MASK) >> ACTION_OFFSET;
-        }
-
-        /**
-         * @param index The first argument for a given action <code>index</code>.
-         */
-        public int getFirstArgument(int index) {
-            return (mActionSequence[index] & FIRST_ARGUMENT_MASK) >> FIRST_ARGUMENT_OFFSET;
-        }
-
-        /**
-         * @param index The second argument for a given action <code>index</code>.
-         */
-        public int getSecondArgument(int index) {
-            return (mActionSequence[index] & SECOND_ARGUMENT_MASK) >> SECOND_ARGUMENT_OFFSET;
-        }
-
-        /**
-         * @param index The third argument for a given action <code>index</code>.
-         */
-        public int getThirdArgument(int index) {
-            return (mActionSequence[index] & THIRD_ARGUMENT_MASK) >> THIRD_ARGUMENT_OFFSET;
-        }
-
-        /**
-         * Creates a new instance.
-         * @param keyCodeAndModifiers The key for the binding (key and modifiers).
-         * @param actionSequence The sequence of action for the binding.
-         */
-        public AccessibilityWebContentKeyBinding(long keyCodeAndModifiers, int[] actionSequence) {
-            mKeyCodeAndModifiers = keyCodeAndModifiers;
-            mActionSequence = actionSequence;
-        }
-
-        @Override
-        public String toString() {
-            StringBuilder builder = new StringBuilder();
-            builder.append("modifiers: ");
-            builder.append(getModifiers());
-            builder.append(", keyCode: ");
-            builder.append(getKeyCode());
-            builder.append(", actions[");
-            for (int i = 0, count = getActionCount(); i < count; i++) {
-                builder.append("{actionCode");
-                builder.append(i);
-                builder.append(": ");
-                builder.append(getActionCode(i));
-                builder.append(", firstArgument: ");
-                builder.append(getFirstArgument(i));
-                builder.append(", secondArgument: ");
-                builder.append(getSecondArgument(i));
-                builder.append(", thirdArgument: ");
-                builder.append(getThirdArgument(i));
-                builder.append("}");
-            }
-            builder.append("]");
-            return builder.toString();
-        }
+    /**
+     * @return {@code true} if accessibility is enabled.
+     */
+    private boolean isAccessibilityEnabled() {
+        return mAccessibilityManager.isEnabled();
     }
 }
diff --git a/core/java/android/webkit/AccessibilityInjectorFallback.java b/core/java/android/webkit/AccessibilityInjectorFallback.java
new file mode 100644
index 0000000000000..9bf52ca205842
--- /dev/null
+++ b/core/java/android/webkit/AccessibilityInjectorFallback.java
@@ -0,0 +1,499 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.webkit;
+
+import android.provider.Settings;
+import android.text.TextUtils;
+import android.text.TextUtils.SimpleStringSplitter;
+import android.util.Log;
+import android.view.KeyEvent;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityManager;
+import android.webkit.WebViewCore.EventHub;
+
+import java.util.ArrayList;
+import java.util.Stack;
+
+/**
+ * This class injects accessibility into WebViews with disabled JavaScript or
+ * WebViews with enabled JavaScript but for which we have no accessibility
+ * script to inject.
+ * </p>
+ * Note: To avoid changes in the framework upon changing the available
+ *       navigation axis, or reordering the navigation axis, or changing
+ *       the key bindings, or defining sequence of actions to be bound to
+ *       a given key this class is navigation axis agnostic. It is only
+ *       aware of one navigation axis which is in fact the default behavior
+ *       of webViews while using the DPAD/TrackBall.
+ * </p>
+ * In general a key binding is a mapping from modifiers + key code to
+ * a sequence of actions. For more detail how to specify key bindings refer to
+ * {@link android.provider.Settings.Secure#ACCESSIBILITY_WEB_CONTENT_KEY_BINDINGS}.
+ * </p>
+ * The possible actions are invocations to
+ * {@link #setCurrentAxis(int, boolean, String)}, or
+ * {@link #traverseCurrentAxis(int, boolean, String)}
+ * {@link #traverseGivenAxis(int, int, boolean, String)}
+ * {@link #prefromAxisTransition(int, int, boolean, String)}
+ * referred via the values of:
+ * {@link #ACTION_SET_CURRENT_AXIS},
+ * {@link #ACTION_TRAVERSE_CURRENT_AXIS},
+ * {@link #ACTION_TRAVERSE_GIVEN_AXIS},
+ * {@link #ACTION_PERFORM_AXIS_TRANSITION},
+ * respectively.
+ * The arguments for the action invocation are specified as offset
+ * hexademical pairs. Note the last argument of the invocation
+ * should NOT be specified in the binding as it is provided by
+ * this class. For details about the key binding implementation
+ * refer to {@link AccessibilityWebContentKeyBinding}.
+ */
+class AccessibilityInjectorFallback {
+    private static final String LOG_TAG = "AccessibilityInjector";
+
+    private static final boolean DEBUG = true;
+
+    private static final int ACTION_SET_CURRENT_AXIS = 0;
+    private static final int ACTION_TRAVERSE_CURRENT_AXIS = 1;
+    private static final int ACTION_TRAVERSE_GIVEN_AXIS = 2;
+    private static final int ACTION_PERFORM_AXIS_TRANSITION = 3;
+    private static final int ACTION_TRAVERSE_DEFAULT_WEB_VIEW_BEHAVIOR_AXIS = 4;
+
+    // the default WebView behavior abstracted as a navigation axis
+    private static final int NAVIGATION_AXIS_DEFAULT_WEB_VIEW_BEHAVIOR = 7;
+
+    // these are the same for all instances so make them process wide
+    private static ArrayList<AccessibilityWebContentKeyBinding> sBindings =
+        new ArrayList<AccessibilityWebContentKeyBinding>();
+
+    // handle to the WebViewClassic this injector is associated with.
+    private final WebViewClassic mWebView;
+
+    // events scheduled for sending as soon as we receive the selected text
+    private final Stack<AccessibilityEvent> mScheduledEventStack = new Stack<AccessibilityEvent>();
+
+    // the current traversal axis
+    private int mCurrentAxis = 2; // sentence
+
+    // we need to consume the up if we have handled the last down
+    private boolean mLastDownEventHandled;
+
+    // getting two empty selection strings in a row we let the WebView handle the event
+    private boolean mIsLastSelectionStringNull;
+
+    // keep track of last direction
+    private int mLastDirection;
+
+    /**
+     * Creates a new injector associated with a given {@link WebViewClassic}.
+     *
+     * @param webView The associated WebViewClassic.
+     */
+    public AccessibilityInjectorFallback(WebViewClassic webView) {
+        mWebView = webView;
+        ensureWebContentKeyBindings();
+    }
+
+    /**
+     * Processes a key down <code>event</code>.
+     *
+     * @return True if the event was processed.
+     */
+    public boolean onKeyEvent(KeyEvent event) {
+        // We do not handle ENTER in any circumstances.
+        if (isEnterActionKey(event.getKeyCode())) {
+            return false;
+        }
+
+        if (event.getAction() == KeyEvent.ACTION_UP) {
+            return mLastDownEventHandled;
+        }
+
+        mLastDownEventHandled = false;
+
+        AccessibilityWebContentKeyBinding binding = null;
+        for (AccessibilityWebContentKeyBinding candidate : sBindings) {
+            if (event.getKeyCode() == candidate.getKeyCode()
+                    && event.hasModifiers(candidate.getModifiers())) {
+                binding = candidate;
+                break;
+            }
+        }
+
+        if (binding == null) {
+            return false;
+        }
+
+        for (int i = 0, count = binding.getActionCount(); i < count; i++) {
+            int actionCode = binding.getActionCode(i);
+            String contentDescription = Integer.toHexString(binding.getAction(i));
+            switch (actionCode) {
+                case ACTION_SET_CURRENT_AXIS:
+                    int axis = binding.getFirstArgument(i);
+                    boolean sendEvent = (binding.getSecondArgument(i) == 1);
+                    setCurrentAxis(axis, sendEvent, contentDescription);
+                    mLastDownEventHandled = true;
+                    break;
+                case ACTION_TRAVERSE_CURRENT_AXIS:
+                    int direction = binding.getFirstArgument(i);
+                    // on second null selection string in same direction - WebView handles the event
+                    if (direction == mLastDirection && mIsLastSelectionStringNull) {
+                        mIsLastSelectionStringNull = false;
+                        return false;
+                    }
+                    mLastDirection = direction;
+                    sendEvent = (binding.getSecondArgument(i) == 1);
+                    mLastDownEventHandled = traverseCurrentAxis(direction, sendEvent,
+                            contentDescription);
+                    break;
+                case ACTION_TRAVERSE_GIVEN_AXIS:
+                    direction = binding.getFirstArgument(i);
+                    // on second null selection string in same direction => WebView handle the event
+                    if (direction == mLastDirection && mIsLastSelectionStringNull) {
+                        mIsLastSelectionStringNull = false;
+                        return false;
+                    }
+                    mLastDirection = direction;
+                    axis =  binding.getSecondArgument(i);
+                    sendEvent = (binding.getThirdArgument(i) == 1);
+                    traverseGivenAxis(direction, axis, sendEvent, contentDescription);
+                    mLastDownEventHandled = true;
+                    break;
+                case ACTION_PERFORM_AXIS_TRANSITION:
+                    int fromAxis = binding.getFirstArgument(i);
+                    int toAxis = binding.getSecondArgument(i);
+                    sendEvent = (binding.getThirdArgument(i) == 1);
+                    prefromAxisTransition(fromAxis, toAxis, sendEvent, contentDescription);
+                    mLastDownEventHandled = true;
+                    break;
+                case ACTION_TRAVERSE_DEFAULT_WEB_VIEW_BEHAVIOR_AXIS:
+                    // This is a special case since we treat the default WebView navigation
+                    // behavior as one of the possible navigation axis the user can use.
+                    // If we are not on the default WebView navigation axis this is NOP.
+                    if (mCurrentAxis == NAVIGATION_AXIS_DEFAULT_WEB_VIEW_BEHAVIOR) {
+                        // While WebVew handles navigation we do not get null selection
+                        // strings so do not check for that here as the cases above.
+                        mLastDirection = binding.getFirstArgument(i);
+                        sendEvent = (binding.getSecondArgument(i) == 1);
+                        traverseGivenAxis(mLastDirection, NAVIGATION_AXIS_DEFAULT_WEB_VIEW_BEHAVIOR,
+                            sendEvent, contentDescription);
+                        mLastDownEventHandled = false;
+                    } else {
+                        mLastDownEventHandled = true;
+                    }
+                    break;
+                default:
+                    Log.w(LOG_TAG, "Unknown action code: " + actionCode);
+            }
+        }
+
+        return mLastDownEventHandled;
+    }
+
+    /**
+     * Set the current navigation axis which will be used while
+     * calling {@link #traverseCurrentAxis(int, boolean, String)}.
+     *
+     * @param axis The axis to set.
+     * @param sendEvent Whether to send an accessibility event to
+     *        announce the change.
+     */
+    private void setCurrentAxis(int axis, boolean sendEvent, String contentDescription) {
+        mCurrentAxis = axis;
+        if (sendEvent) {
+            AccessibilityEvent event = getPartialyPopulatedAccessibilityEvent();
+            event.getText().add(String.valueOf(axis));
+            event.setContentDescription(contentDescription);
+            sendAccessibilityEvent(event);
+        }
+    }
+
+    /**
+     * Performs conditional transition one axis to another.
+     *
+     * @param fromAxis The axis which must be the current for the transition to occur.
+     * @param toAxis The axis to which to transition.
+     * @param sendEvent Flag if to send an event to announce successful transition.
+     * @param contentDescription A description of the performed action.
+     */
+    private void prefromAxisTransition(int fromAxis, int toAxis, boolean sendEvent,
+            String contentDescription) {
+        if (mCurrentAxis == fromAxis) {
+            setCurrentAxis(toAxis, sendEvent, contentDescription);
+        }
+    }
+
+    /**
+     * Traverse the document along the current navigation axis.
+     *
+     * @param direction The direction of traversal.
+     * @param sendEvent Whether to send an accessibility event to
+     *        announce the change.
+     * @param contentDescription A description of the performed action.
+     * @see #setCurrentAxis(int, boolean, String)
+     */
+    private boolean traverseCurrentAxis(int direction, boolean sendEvent,
+            String contentDescription) {
+        return traverseGivenAxis(direction, mCurrentAxis, sendEvent, contentDescription);
+    }
+
+    /**
+     * Traverse the document along the given navigation axis.
+     *
+     * @param direction The direction of traversal.
+     * @param axis The axis along which to traverse.
+     * @param sendEvent Whether to send an accessibility event to
+     *        announce the change.
+     * @param contentDescription A description of the performed action.
+     */
+    private boolean traverseGivenAxis(int direction, int axis, boolean sendEvent,
+            String contentDescription) {
+        WebViewCore webViewCore = mWebView.getWebViewCore();
+        if (webViewCore == null) {
+            return false;
+        }
+
+        AccessibilityEvent event = null;
+        if (sendEvent) {
+            event = getPartialyPopulatedAccessibilityEvent();
+            // the text will be set upon receiving the selection string
+            event.setContentDescription(contentDescription);
+        }
+        mScheduledEventStack.push(event);
+
+        // if the axis is the default let WebView handle the event which will
+        // result in cursor ring movement and selection of its content
+        if (axis == NAVIGATION_AXIS_DEFAULT_WEB_VIEW_BEHAVIOR) {
+            return false;
+        }
+
+        webViewCore.sendMessage(EventHub.MODIFY_SELECTION, direction, axis);
+        return true;
+    }
+
+    /**
+     * Called when the <code>selectionString</code> has changed.
+     */
+    public void onSelectionStringChange(String selectionString) {
+        if (DEBUG) {
+            Log.d(LOG_TAG, "Selection string: " + selectionString);
+        }
+        mIsLastSelectionStringNull = (selectionString == null);
+        if (mScheduledEventStack.isEmpty()) {
+            return;
+        }
+        AccessibilityEvent event = mScheduledEventStack.pop();
+        if (event != null) {
+            event.getText().add(selectionString);
+            sendAccessibilityEvent(event);
+        }
+    }
+
+    /**
+     * Sends an {@link AccessibilityEvent}.
+     *
+     * @param event The event to send.
+     */
+    private void sendAccessibilityEvent(AccessibilityEvent event) {
+        if (DEBUG) {
+            Log.d(LOG_TAG, "Dispatching: " + event);
+        }
+        // accessibility may be disabled while waiting for the selection string
+        AccessibilityManager accessibilityManager =
+            AccessibilityManager.getInstance(mWebView.getContext());
+        if (accessibilityManager.isEnabled()) {
+            accessibilityManager.sendAccessibilityEvent(event);
+        }
+    }
+
+    /**
+     * @return An accessibility event whose members are populated except its
+     *         text and content description.
+     */
+    private AccessibilityEvent getPartialyPopulatedAccessibilityEvent() {
+        AccessibilityEvent event = AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_SELECTED);
+        event.setClassName(mWebView.getClass().getName());
+        event.setPackageName(mWebView.getContext().getPackageName());
+        event.setEnabled(mWebView.getWebView().isEnabled());
+        return event;
+    }
+
+    /**
+     * Ensures that the Web content key bindings are loaded.
+     */
+    private void ensureWebContentKeyBindings() {
+        if (sBindings.size() > 0) {
+            return;
+        }
+
+        String webContentKeyBindingsString  = Settings.Secure.getString(
+                mWebView.getContext().getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_WEB_CONTENT_KEY_BINDINGS);
+
+        SimpleStringSplitter semiColonSplitter = new SimpleStringSplitter(';');
+        semiColonSplitter.setString(webContentKeyBindingsString);
+
+        while (semiColonSplitter.hasNext()) {
+            String bindingString = semiColonSplitter.next();
+            if (TextUtils.isEmpty(bindingString)) {
+                Log.e(LOG_TAG, "Disregarding malformed Web content key binding: "
+                        + webContentKeyBindingsString);
+                continue;
+            }
+            String[] keyValueArray = bindingString.split("=");
+            if (keyValueArray.length != 2) {
+                Log.e(LOG_TAG, "Disregarding malformed Web content key binding: " + bindingString);
+                continue;
+            }
+            try {
+                long keyCodeAndModifiers = Long.decode(keyValueArray[0].trim());
+                String[] actionStrings = keyValueArray[1].split(":");
+                int[] actions = new int[actionStrings.length];
+                for (int i = 0, count = actions.length; i < count; i++) {
+                    actions[i] = Integer.decode(actionStrings[i].trim());
+                }
+                sBindings.add(new AccessibilityWebContentKeyBinding(keyCodeAndModifiers, actions));
+            } catch (NumberFormatException nfe) {
+                Log.e(LOG_TAG, "Disregarding malformed key binding: " + bindingString);
+            }
+        }
+    }
+
+    private boolean isEnterActionKey(int keyCode) {
+        return keyCode == KeyEvent.KEYCODE_DPAD_CENTER
+                || keyCode == KeyEvent.KEYCODE_ENTER
+                || keyCode == KeyEvent.KEYCODE_NUMPAD_ENTER;
+    }
+
+    /**
+     * Represents a web content key-binding.
+     */
+    private static final class AccessibilityWebContentKeyBinding {
+
+        private static final int MODIFIERS_OFFSET = 32;
+        private static final long MODIFIERS_MASK = 0xFFFFFFF00000000L;
+
+        private static final int KEY_CODE_OFFSET = 0;
+        private static final long KEY_CODE_MASK = 0x00000000FFFFFFFFL;
+
+        private static final int ACTION_OFFSET = 24;
+        private static final int ACTION_MASK = 0xFF000000;
+
+        private static final int FIRST_ARGUMENT_OFFSET = 16;
+        private static final int FIRST_ARGUMENT_MASK = 0x00FF0000;
+
+        private static final int SECOND_ARGUMENT_OFFSET = 8;
+        private static final int SECOND_ARGUMENT_MASK = 0x0000FF00;
+
+        private static final int THIRD_ARGUMENT_OFFSET = 0;
+        private static final int THIRD_ARGUMENT_MASK = 0x000000FF;
+
+        private final long mKeyCodeAndModifiers;
+
+        private final int [] mActionSequence;
+
+        /**
+         * @return The key code of the binding key.
+         */
+        public int getKeyCode() {
+            return (int) ((mKeyCodeAndModifiers & KEY_CODE_MASK) >> KEY_CODE_OFFSET);
+        }
+
+        /**
+         * @return The meta state of the binding key.
+         */
+        public int getModifiers() {
+            return (int) ((mKeyCodeAndModifiers & MODIFIERS_MASK) >> MODIFIERS_OFFSET);
+        }
+
+        /**
+         * @return The number of actions in the key binding.
+         */
+        public int getActionCount() {
+            return mActionSequence.length;
+        }
+
+        /**
+         * @param index The action for a given action <code>index</code>.
+         */
+        public int getAction(int index) {
+            return mActionSequence[index];
+        }
+
+        /**
+         * @param index The action code for a given action <code>index</code>.
+         */
+        public int getActionCode(int index) {
+            return (mActionSequence[index] & ACTION_MASK) >> ACTION_OFFSET;
+        }
+
+        /**
+         * @param index The first argument for a given action <code>index</code>.
+         */
+        public int getFirstArgument(int index) {
+            return (mActionSequence[index] & FIRST_ARGUMENT_MASK) >> FIRST_ARGUMENT_OFFSET;
+        }
+
+        /**
+         * @param index The second argument for a given action <code>index</code>.
+         */
+        public int getSecondArgument(int index) {
+            return (mActionSequence[index] & SECOND_ARGUMENT_MASK) >> SECOND_ARGUMENT_OFFSET;
+        }
+
+        /**
+         * @param index The third argument for a given action <code>index</code>.
+         */
+        public int getThirdArgument(int index) {
+            return (mActionSequence[index] & THIRD_ARGUMENT_MASK) >> THIRD_ARGUMENT_OFFSET;
+        }
+
+        /**
+         * Creates a new instance.
+         * @param keyCodeAndModifiers The key for the binding (key and modifiers).
+         * @param actionSequence The sequence of action for the binding.
+         */
+        public AccessibilityWebContentKeyBinding(long keyCodeAndModifiers, int[] actionSequence) {
+            mKeyCodeAndModifiers = keyCodeAndModifiers;
+            mActionSequence = actionSequence;
+        }
+
+        @Override
+        public String toString() {
+            StringBuilder builder = new StringBuilder();
+            builder.append("modifiers: ");
+            builder.append(getModifiers());
+            builder.append(", keyCode: ");
+            builder.append(getKeyCode());
+            builder.append(", actions[");
+            for (int i = 0, count = getActionCount(); i < count; i++) {
+                builder.append("{actionCode");
+                builder.append(i);
+                builder.append(": ");
+                builder.append(getActionCode(i));
+                builder.append(", firstArgument: ");
+                builder.append(getFirstArgument(i));
+                builder.append(", secondArgument: ");
+                builder.append(getSecondArgument(i));
+                builder.append(", thirdArgument: ");
+                builder.append(getThirdArgument(i));
+                builder.append("}");
+            }
+            builder.append("]");
+            return builder.toString();
+        }
+    }
+}
diff --git a/core/java/android/webkit/WebViewClassic.java b/core/java/android/webkit/WebViewClassic.java
index f1f3db233568d..eee45ca960ea0 100644
--- a/core/java/android/webkit/WebViewClassic.java
+++ b/core/java/android/webkit/WebViewClassic.java
@@ -60,9 +60,7 @@ import android.os.Handler;
 import android.os.Looper;
 import android.os.Message;
 import android.os.SystemClock;
-import android.provider.Settings;
 import android.security.KeyChain;
-import android.speech.tts.TextToSpeech;
 import android.text.Editable;
 import android.text.InputType;
 import android.text.Selection;
@@ -867,15 +865,9 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
     private static final int MOTIONLESS_IGNORE          = 3;
     private int mHeldMotionless;
 
-    // An instance for injecting accessibility in WebViews with disabled
-    // JavaScript or ones for which no accessibility script exists
+    // Lazily-instantiated instance for injecting accessibility.
     private AccessibilityInjector mAccessibilityInjector;
 
-    // flag indicating if accessibility script is injected so we
-    // know to handle Shift and arrows natively first
-    private boolean mAccessibilityScriptInjected;
-
-
     /**
      * How long the caret handle will last without being touched.
      */
@@ -1085,34 +1077,6 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
     private int mHorizontalScrollBarMode = SCROLLBAR_AUTO;
     private int mVerticalScrollBarMode = SCROLLBAR_AUTO;
 
-    // constants for determining script injection strategy
-    private static final int ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED = -1;
-    private static final int ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT = 0;
-    private static final int ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED = 1;
-
-    // the alias via which accessibility JavaScript interface is exposed
-    private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE = "accessibility";
-
-    // Template for JavaScript that injects a screen-reader.
-    private static final String ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE =
-        "javascript:(function() {" +
-        "    var chooser = document.createElement('script');" +
-        "    chooser.type = 'text/javascript';" +
-        "    chooser.src = '%1s';" +
-        "    document.getElementsByTagName('head')[0].appendChild(chooser);" +
-        "  })();";
-
-    // Regular expression that matches the "axs" URL parameter.
-    // The value of 0 means the accessibility script is opted out
-    // The value of 1 means the accessibility script is already injected
-    private static final String PATTERN_MATCH_AXS_URL_PARAMETER = "(\\?axs=(0|1))|(&axs=(0|1))";
-
-    // TextToSpeech instance exposed to JavaScript to the injected screenreader.
-    private TextToSpeech mTextToSpeech;
-
-    // variable to cache the above pattern in case accessibility is enabled.
-    private Pattern mMatchAxsUrlParameterPattern;
-
     /**
      * Max distance to overscroll by in pixels.
      * This how far content can be pulled beyond its normal bounds by the user.
@@ -1633,40 +1597,6 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
         return true;
     }
 
-    /**
-     * Adds accessibility APIs to JavaScript.
-     *
-     * Note: This method is responsible to performing the necessary
-     *       check if the accessibility APIs should be exposed.
-     */
-    private void addAccessibilityApisToJavaScript() {
-        if (AccessibilityManager.getInstance(mContext).isEnabled()
-                && getSettings().getJavaScriptEnabled()) {
-            // exposing the TTS for now ...
-            final Context ctx = mContext;
-            if (ctx != null) {
-                final String packageName = ctx.getPackageName();
-                if (packageName != null) {
-                    mTextToSpeech = new TextToSpeech(ctx, null, null,
-                            packageName + ".**webview**", true);
-                    addJavascriptInterface(mTextToSpeech, ALIAS_ACCESSIBILITY_JS_INTERFACE);
-                }
-            }
-        }
-    }
-
-    /**
-     * Removes accessibility APIs from JavaScript.
-     */
-    private void removeAccessibilityApisFromJavaScript() {
-        // exposing the TTS for now ...
-        if (mTextToSpeech != null) {
-            removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE);
-            mTextToSpeech.shutdown();
-            mTextToSpeech = null;
-        }
-    }
-
     @Override
     public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
         info.setScrollable(isScrollableForAccessibility());
@@ -1687,6 +1617,17 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
         event.setMaxScrollY(Math.max(convertedContentHeight - adjustedViewHeight, 0));
     }
 
+    private boolean isAccessibilityEnabled() {
+        return AccessibilityManager.getInstance(mContext).isEnabled();
+    }
+
+    private AccessibilityInjector getAccessibilityInjector() {
+        if (mAccessibilityInjector == null) {
+            mAccessibilityInjector = new AccessibilityInjector(this);
+        }
+        return mAccessibilityInjector;
+    }
+
     private boolean isScrollableForAccessibility() {
         return (contentToViewX(getContentWidth()) > getWidth() - mWebView.getPaddingLeft()
                 - mWebView.getPaddingRight()
@@ -3828,7 +3769,9 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
 
         // reset the flag since we set to true in if need after
         // loading is see onPageFinished(Url)
-        mAccessibilityScriptInjected = false;
+        if (isAccessibilityEnabled()) {
+            getAccessibilityInjector().onPageStarted(url);
+        }
 
         // Don't start out editing.
         mIsEditingText = false;
@@ -3840,114 +3783,10 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
      */
     /* package */ void onPageFinished(String url) {
         mZoomManager.onPageFinished(url);
-        injectAccessibilityForUrl(url);
-    }
 
-    /**
-     * This method injects accessibility in the loaded document if accessibility
-     * is enabled. If JavaScript is enabled we try to inject a URL specific script.
-     * If no URL specific script is found or JavaScript is disabled we fallback to
-     * the default {@link AccessibilityInjector} implementation.
-     * </p>
-     * If the URL has the "axs" paramter set to 1 it has already done the
-     * script injection so we do nothing. If the parameter is set to 0
-     * the URL opts out accessibility script injection so we fall back to
-     * the default {@link AccessibilityInjector}.
-     * </p>
-     * Note: If the user has not opted-in the accessibility script injection no scripts
-     * are injected rather the default {@link AccessibilityInjector} implementation
-     * is used.
-     *
-     * @param url The URL loaded by this {@link WebView}.
-     */
-    private void injectAccessibilityForUrl(String url) {
-        if (mWebViewCore == null) {
-            return;
+        if (isAccessibilityEnabled()) {
+            getAccessibilityInjector().onPageFinished(url);
         }
-        AccessibilityManager accessibilityManager = AccessibilityManager.getInstance(mContext);
-
-        if (!accessibilityManager.isEnabled()) {
-            // it is possible that accessibility was turned off between reloads
-            ensureAccessibilityScriptInjectorInstance(false);
-            return;
-        }
-
-        if (!getSettings().getJavaScriptEnabled()) {
-            // no JS so we fallback to the basic buil-in support
-            ensureAccessibilityScriptInjectorInstance(true);
-            return;
-        }
-
-        // check the URL "axs" parameter to choose appropriate action
-        int axsParameterValue = getAxsUrlParameterValue(url);
-        if (axsParameterValue == ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED) {
-            boolean onDeviceScriptInjectionEnabled = (Settings.Secure.getInt(mContext
-                    .getContentResolver(), Settings.Secure.ACCESSIBILITY_SCRIPT_INJECTION, 0) == 1);
-            if (onDeviceScriptInjectionEnabled) {
-                ensureAccessibilityScriptInjectorInstance(false);
-                // neither script injected nor script injection opted out => we inject
-                mWebView.loadUrl(getScreenReaderInjectingJs());
-                // TODO: Set this flag after successfull script injection. Maybe upon injection
-                // the chooser should update the meta tag and we check it to declare success
-                mAccessibilityScriptInjected = true;
-            } else {
-                // injection disabled so we fallback to the basic built-in support
-                ensureAccessibilityScriptInjectorInstance(true);
-            }
-        } else if (axsParameterValue == ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT) {
-            // injection opted out so we fallback to the basic buil-in support
-            ensureAccessibilityScriptInjectorInstance(true);
-        } else if (axsParameterValue == ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED) {
-            ensureAccessibilityScriptInjectorInstance(false);
-            // the URL provides accessibility but we still need to add our generic script
-            mWebView.loadUrl(getScreenReaderInjectingJs());
-        } else {
-            Log.e(LOGTAG, "Unknown URL value for the \"axs\" URL parameter: " + axsParameterValue);
-        }
-    }
-
-    /**
-     * Ensures the instance of the {@link AccessibilityInjector} to be present ot not.
-     *
-     * @param present True to ensure an insance, false to ensure no instance.
-     */
-    private void ensureAccessibilityScriptInjectorInstance(boolean present) {
-        if (present) {
-            if (mAccessibilityInjector == null) {
-                mAccessibilityInjector = new AccessibilityInjector(this);
-            }
-        } else {
-            mAccessibilityInjector = null;
-        }
-    }
-
-    /**
-     * Gets JavaScript that injects a screen-reader.
-     *
-     * @return The JavaScript snippet.
-     */
-    private String getScreenReaderInjectingJs() {
-        String screenReaderUrl = Settings.Secure.getString(mContext.getContentResolver(),
-                Settings.Secure.ACCESSIBILITY_SCREEN_READER_URL);
-        return String.format(ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE, screenReaderUrl);
-    }
-
-    /**
-     * Gets the "axs" URL parameter value.
-     *
-     * @param url A url to fetch the paramter from.
-     * @return The parameter value if such, -1 otherwise.
-     */
-    private int getAxsUrlParameterValue(String url) {
-        if (mMatchAxsUrlParameterPattern == null) {
-            mMatchAxsUrlParameterPattern = Pattern.compile(PATTERN_MATCH_AXS_URL_PARAMETER);
-        }
-        Matcher matcher = mMatchAxsUrlParameterPattern.matcher(url);
-        if (matcher.find()) {
-            String keyValuePair = url.substring(matcher.start(), matcher.end());
-            return Integer.parseInt(keyValuePair.split("=")[1]);
-        }
-        return -1;
     }
 
     // scale from content to view coordinates, and pin
@@ -4909,30 +4748,10 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
             return false;
         }
 
-        // accessibility support
-        if (accessibilityScriptInjected()) {
-            if (AccessibilityManager.getInstance(mContext).isEnabled()) {
-                // if an accessibility script is injected we delegate to it the key handling.
-                // this script is a screen reader which is a fully fledged solution for blind
-                // users to navigate in and interact with web pages.
-                sendBatchableInputMessage(EventHub.KEY_DOWN, 0, 0, event);
-                return true;
-            } else {
-                // Clean up if accessibility was disabled after loading the current URL.
-                mAccessibilityScriptInjected = false;
-            }
-        } else if (mAccessibilityInjector != null) {
-            if (AccessibilityManager.getInstance(mContext).isEnabled()) {
-                if (mAccessibilityInjector.onKeyEvent(event)) {
-                    // if an accessibility injector is present (no JavaScript enabled or the site
-                    // opts out injecting our JavaScript screen reader) we let it decide whether
-                    // to act on and consume the event.
-                    return true;
-                }
-            } else {
-                // Clean up if accessibility was disabled after loading the current URL.
-                mAccessibilityInjector = null;
-            }
+        // See if the accessibility injector needs to handle this event.
+        if (isAccessibilityEnabled()
+                && getAccessibilityInjector().handleKeyEventIfNecessary(event)) {
+            return true;
         }
 
         if (keyCode == KeyEvent.KEYCODE_PAGE_UP) {
@@ -5036,30 +4855,10 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
             return false;
         }
 
-        // accessibility support
-        if (accessibilityScriptInjected()) {
-            if (AccessibilityManager.getInstance(mContext).isEnabled()) {
-                // if an accessibility script is injected we delegate to it the key handling.
-                // this script is a screen reader which is a fully fledged solution for blind
-                // users to navigate in and interact with web pages.
-                sendBatchableInputMessage(EventHub.KEY_UP, 0, 0, event);
-                return true;
-            } else {
-                // Clean up if accessibility was disabled after loading the current URL.
-                mAccessibilityScriptInjected = false;
-            }
-        } else if (mAccessibilityInjector != null) {
-            if (AccessibilityManager.getInstance(mContext).isEnabled()) {
-                if (mAccessibilityInjector.onKeyEvent(event)) {
-                    // if an accessibility injector is present (no JavaScript enabled or the site
-                    // opts out injecting our JavaScript screen reader) we let it decide whether to
-                    // act on and consume the event.
-                    return true;
-                }
-            } else {
-                // Clean up if accessibility was disabled after loading the current URL.
-                mAccessibilityInjector = null;
-            }
+        // See if the accessibility injector needs to handle this event.
+        if (isAccessibilityEnabled()
+                && getAccessibilityInjector().handleKeyEventIfNecessary(event)) {
+            return true;
         }
 
         if (isEnterActionKey(keyCode)) {
@@ -5360,7 +5159,9 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
     public void onAttachedToWindow() {
         if (mWebView.hasWindowFocus()) setActive(true);
 
-        addAccessibilityApisToJavaScript();
+        if (isAccessibilityEnabled()) {
+            getAccessibilityInjector().addAccessibilityApisIfNecessary();
+        }
 
         updateHwAccelerated();
     }
@@ -5371,7 +5172,14 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
         mZoomManager.dismissZoomPicker();
         if (mWebView.hasWindowFocus()) setActive(false);
 
-        removeAccessibilityApisFromJavaScript();
+        if (isAccessibilityEnabled()) {
+            getAccessibilityInjector().removeAccessibilityApisIfNecessary();
+        } else {
+            // Ensure the injector is cleared if we're detaching from the window
+            // and accessibility is disabled.
+            mAccessibilityInjector = null;
+        }
+
         updateHwAccelerated();
 
         if (mWebView.isHardwareAccelerated()) {
@@ -7467,9 +7275,9 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
                     break;
 
                 case SELECTION_STRING_CHANGED:
-                    if (mAccessibilityInjector != null) {
-                        String selectionString = (String) msg.obj;
-                        mAccessibilityInjector.onSelectionStringChange(selectionString);
+                    if (isAccessibilityEnabled()) {
+                        getAccessibilityInjector()
+                                .handleSelectionChangedIfNecessary((String) msg.obj);
                     }
                     break;
 
@@ -8025,7 +7833,7 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
         mIsBatchingTextChanges = false;
     }
 
-    private void sendBatchableInputMessage(int what, int arg1, int arg2,
+    void sendBatchableInputMessage(int what, int arg1, int arg2,
             Object obj) {
         if (mWebViewCore == null) {
             return;
@@ -8445,16 +8253,6 @@ public final class WebViewClassic implements WebViewProvider, WebViewProvider.Sc
         sendBatchableInputMessage(eventHubAction, direction, 0, event);
     }
 
-    /**
-     * @return Whether accessibility script has been injected.
-     */
-    private boolean accessibilityScriptInjected() {
-        // TODO: Maybe the injected script should announce its presence in
-        // the page meta-tag so the nativePageShouldHandleShiftAndArrows
-        // will check that as one of the conditions it looks for
-        return mAccessibilityScriptInjected;
-    }
-
     /**
      * See {@link WebView#setBackgroundColor(int)}
      */