Always send TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED.

This logic was borrowed from ExploreByTouchHelper, but apparently it's wrong,
because TalkBack sends ACTION_ACCESSIBILITY_FOCUS on a new view id and
then ACTION_CLEAR_ACCESSIBILITY_FOCUS on the old view id, and since we didn't
think the old view had accessibility focus, we never responded with
a TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED event, so the framework would sometimes
not update its cache, and TalkBack could think the old view still had
accessibility focus.

BUG=458343

Review URL: https://codereview.chromium.org/916213003

Cr-Commit-Position: refs/heads/master@{#316238}

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

@@ -211,9 +211,11 @@ public class BrowserAccessibilityManager {
                 }
                 return true;
             case AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS:
+                // ALWAYS respond with TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED whether we thought
+                // it had focus or not, so that the Android framework cache is correct.
+                sendAccessibilityEvent(virtualViewId,
+                        AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
                 if (mAccessibilityFocusId == virtualViewId) {
-                    sendAccessibilityEvent(mAccessibilityFocusId,
-                            AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
                     mAccessibilityFocusId = View.NO_ID;
                     mAccessibilityFocusRect = null;
                 }