DO NOT MERGE Cherry-Pick: Add ViewConfiguration.getScaledScrollFactor()

This value is used to convert ACTION_SCROLL axis values into raw
pixel distances.

CP of ag/1333603 from master to feldspar-dev. New method is @hide and
@SystemApi in this version. In master, it's part of the new public
API, but feldspar will launch before O.

Change-Id: I5ee73ebcd183c43939ae8aa157e88489e05d4760

core/java/android/view/ViewConfiguration.java

@@ -16,6 +16,7 @@
 
 package android.view;
 
+import android.annotation.SystemApi;
 import android.app.AppGlobals;
 import android.content.Context;
 import android.content.res.Configuration;
@@ -218,6 +219,12 @@ public class ViewConfiguration {
      */
     private static final int OVERFLING_DISTANCE = 6;
 
+    /**
+     * Amount to scroll in response to a {@link MotionEvent#ACTION_SCROLL} event, in dips per
+     * axis value.
+     */
+    private static final int SCROLL_FACTOR = 64;
+
     /**
      * Default duration to hide an action mode for.
      */
@@ -246,6 +253,7 @@ public class ViewConfiguration {
     private final int mOverflingDistance;
     private final boolean mFadingMarqueeEnabled;
     private final long mGlobalActionsKeyTimeout;
+    private final int mScrollFactor;
 
     private boolean sHasPermanentMenuKey;
     private boolean sHasPermanentMenuKeySet;
@@ -274,6 +282,7 @@ public class ViewConfiguration {
         mOverflingDistance = OVERFLING_DISTANCE;
         mFadingMarqueeEnabled = true;
         mGlobalActionsKeyTimeout = GLOBAL_ACTIONS_KEY_TIMEOUT;
+        mScrollFactor = SCROLL_FACTOR;
     }
 
     /**
@@ -357,6 +366,8 @@ public class ViewConfiguration {
                 com.android.internal.R.dimen.config_viewMaxFlingVelocity);
         mGlobalActionsKeyTimeout = res.getInteger(
                 com.android.internal.R.integer.config_globalActionsKeyTimeout);
+        mScrollFactor = res.getDimensionPixelSize(
+                com.android.internal.R.dimen.config_scrollFactor);
     }
 
     /**
@@ -668,6 +679,16 @@ public class ViewConfiguration {
         return mMaximumFlingVelocity;
     }
 
+    /**
+     * @return Amount to scroll in response to a {@link MotionEvent#ACTION_SCROLL} event. Multiply
+     * this by the event's axis value to obtain the number of pixels to be scrolled.
+     * @hide
+     * @SystemApi
+     */
+    public int getScaledScrollFactor() {
+        return mScrollFactor;
+    }
+
     /**
      * The maximum drawing cache size expressed in bytes.
      *

core/res/res/values/config.xml

@@ -1753,6 +1753,10 @@
     <!-- Amount of time in ms the user needs to press the relevant key to bring up the global actions dialog -->
     <integer name="config_globalActionsKeyTimeout">500</integer>
 
+    <!-- Distance that should be scrolled in response to a {@link MotionEvent#ACTION_SCROLL event}
+         with an axis value of 1. -->
+    <dimen name="config_scrollFactor">64dp</dimen>
+
     <!-- Maximum number of grid columns permitted in the ResolverActivity
          used for picking activities to handle an intent. -->
     <integer name="config_maxResolverActivityColumns">3</integer>

core/res/res/values/symbols.xml

@@ -416,6 +416,7 @@
   <java-symbol type="dimen" name="config_viewConfigurationTouchSlop" />
   <java-symbol type="dimen" name="config_viewMinFlingVelocity" />
   <java-symbol type="dimen" name="config_viewMaxFlingVelocity" />
+  <java-symbol type="dimen" name="config_scrollFactor" />
   <java-symbol type="dimen" name="default_app_widget_padding_bottom" />
   <java-symbol type="dimen" name="default_app_widget_padding_left" />
   <java-symbol type="dimen" name="default_app_widget_padding_right" />