Only set accessibility focus on page load for browser tabs, not web views.

BUG=406053

Review URL: https://codereview.chromium.org/490333002

Cr-Commit-Position: refs/heads/master@{#291713}

chrome/android/java/src/org/chromium/chrome/browser/Tab.java

@@ -830,6 +830,11 @@ public class Tab implements NavigationClient {
         }
 
         for (TabObserver observer : mObservers) observer.onContentChanged(this);
+
+        // For browser tabs, we want to set accessibility focus to the page
+        // when it loads. This is not the default behavior for embedded
+        // web views.
+        mContentViewCore.setShouldSetAccessibilityFocusOnPageLoad(true);
     }
 
     /**

content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

@@ -295,6 +295,12 @@ public class ContentViewCore
     // Accessibility touch exploration state.
     private boolean mTouchExplorationEnabled;
 
+    // Whether accessibility focus should be set to the page when it finishes loading.
+    // This only applies if an accessibility service like TalkBack is running.
+    // This is desirable behavior for a browser window, but not for an embedded
+    // WebView.
+    private boolean mShouldSetAccessibilityFocusOnPageLoad;
+
     // Allows us to dynamically respond when the accessibility script injection flag changes.
     private ContentObserver mAccessibilityScriptInjectionObserver;
 
@@ -2878,6 +2884,23 @@ public class ContentViewCore
         mAccessibilityInjector.onPageLostFocus();
     }
 
+    /**
+     * Return whether or not we should set accessibility focus on page load.
+     */
+    public boolean shouldSetAccessibilityFocusOnPageLoad() {
+        return mShouldSetAccessibilityFocusOnPageLoad;
+    }
+
+    /**
+     * Return whether or not we should set accessibility focus on page load.
+     * This only applies if an accessibility service like TalkBack is running.
+     * This is desirable behavior for a browser window, but not for an embedded
+     * WebView.
+     */
+    public void setShouldSetAccessibilityFocusOnPageLoad(boolean on) {
+        mShouldSetAccessibilityFocusOnPageLoad = on;
+    }
+
     /**
      * Inform WebKit that Fullscreen mode has been exited by the user.
      */

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

@@ -370,9 +370,11 @@ public class BrowserAccessibilityManager {
     private void handlePageLoaded(int id) {
         if (mUserHasTouchExplored) return;
 
+        if (mContentViewCore.shouldSetAccessibilityFocusOnPageLoad()) {
             mAccessibilityFocusId = id;
             sendAccessibilityEvent(id, AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
         }
+    }
 
     @CalledByNative
     private void handleFocusChanged(int id) {