Re-focus node with Android accessibility focus when it moves

This is a workaround for an Android accessibility bug - when the object with accessibility focus moves, Android doesn't update the bounds of accessibility focus on the screen, even if we send a WINDOW_CONTENT_CHANGED event.

With this change, we keep track of the bounding rect of the node with accessibility focus, and if it changes, we move focus to the document and then back to this node, which works around the issue.

No visual flicker was observed when testing on multiple devices. Refreshable braille displays flicker briefly.

BUG=407871

Review URL: https://codereview.chromium.org/505423002

Cr-Commit-Position: refs/heads/master@{#292402}

content/browser/accessibility/browser_accessibility_manager_android.cc

@@ -247,6 +247,7 @@ jboolean BrowserAccessibilityManagerAndroid::PopulateAccessibilityNodeInfo(
   bool is_root = node->GetParent() == NULL;
   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoLocation(
       env, obj, info,
+      id,
       absolute_rect.x(), absolute_rect.y(),
       parent_relative_rect.x(), parent_relative_rect.y(),
       absolute_rect.width(), absolute_rect.height(),

content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java

@@ -45,6 +45,7 @@ public class BrowserAccessibilityManager {
     private final RenderCoordinates mRenderCoordinates;
     private long mNativeObj;
     private int mAccessibilityFocusId;
+    private Rect mAccessibilityFocusRect;
     private boolean mIsHovering;
     private int mLastHoverId = View.NO_ID;
     private int mCurrentRootId;
@@ -178,6 +179,7 @@ public class BrowserAccessibilityManager {
                     sendAccessibilityEvent(mAccessibilityFocusId,
                             AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
                     mAccessibilityFocusId = View.NO_ID;
+                    mAccessibilityFocusRect = null;
                 }
                 return true;
             case AccessibilityNodeInfo.ACTION_CLICK:
@@ -283,6 +285,7 @@ public class BrowserAccessibilityManager {
             return false;
 
         mAccessibilityFocusId = newAccessibilityFocusId;
+        mAccessibilityFocusRect = null;
         sendAccessibilityEvent(mAccessibilityFocusId,
                 AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
         return true;
@@ -426,6 +429,7 @@ public class BrowserAccessibilityManager {
     @CalledByNative
     private void handleNavigate() {
         mAccessibilityFocusId = View.NO_ID;
+        mAccessibilityFocusRect = null;
         mUserHasTouchExplored = false;
         // Invalidate the host, since its child is now gone.
         mView.sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED);
@@ -526,6 +530,7 @@ public class BrowserAccessibilityManager {
 
     @CalledByNative
     private void setAccessibilityNodeInfoLocation(AccessibilityNodeInfo node,
+            final int virtualViewId,
             int absoluteLeft, int absoluteTop, int parentRelativeLeft, int parentRelativeTop,
             int width, int height, boolean isRootNode) {
         // First set the bounds in parent.
@@ -560,6 +565,20 @@ public class BrowserAccessibilityManager {
         rect.offset(viewLocation[0], viewLocation[1]);
 
         node.setBoundsInScreen(rect);
+
+        // Work around a bug in the Android framework where if the object with accessibility
+        // focus moves, the accessibility focus rect is not updated - both the visual highlight,
+        // and the location on the screen that's clicked if you double-tap. To work around this,
+        // when we know the object with accessibility focus moved, move focus away and then
+        // move focus right back to it, which tricks Android into updating its bounds.
+        if (virtualViewId == mAccessibilityFocusId && virtualViewId != mCurrentRootId) {
+            if (mAccessibilityFocusRect == null) {
+                mAccessibilityFocusRect = rect;
+            } else if (!mAccessibilityFocusRect.equals(rect)) {
+                mAccessibilityFocusRect = rect;
+                moveAccessibilityFocusToIdAndRefocusIfNeeded(virtualViewId);
+            }
+        }
     }
 
     @CalledByNative