Auto append password hint for TextView

Some TextViews are made as password via input type but does not
contain autofill password hint. This change auto append a hint
for autofill to identify.

Bug: 219844915
Test: atest android.autofillservice.cts.dialog.LoginActivityTest
Change-Id: Ifd18c56ffe788a601821d178ace41413f9e0454e

core/java/android/view/View.java

@@ -1280,6 +1280,17 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
      */
     public static final String AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DAY = "creditCardExpirationDay";
 
+    /**
+     * A hint indicating that this view can be autofilled with a password.
+     *
+     * This is a heuristic-based hint that is meant to be used by UI Toolkit developers when a
+     * view is a password field but doesn't specify a
+     * <code>{@value View#AUTOFILL_HINT_PASSWORD}</code>.
+     * @hide
+     */
+    // TODO(229765029): unhide this for UI toolkit
+    public static final String AUTOFILL_HINT_PASSWORD_AUTO = "passwordAuto";
+
     /**
      * Hints for the autofill services that describes the content of the view.
      */

core/java/android/widget/TextView.java

@@ -6974,6 +6974,18 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
         mEditor.mInputType = type;
     }
 
+    @Override
+    public String[] getAutofillHints() {
+        String[] hints = super.getAutofillHints();
+        if (isAnyPasswordInputType()) {
+            if (!ArrayUtils.contains(hints, AUTOFILL_HINT_PASSWORD_AUTO)) {
+                hints = ArrayUtils.appendElement(String.class, hints,
+                        AUTOFILL_HINT_PASSWORD_AUTO);
+            }
+        }
+        return hints;
+    }
+
     /**
      * @return {@code null} if the key listener should use pre-O (locale-independent). Otherwise
      *         a {@code Locale} object that can be used to customize key various listeners.