Enable PDF accessibility when RenderFrame's accessibility mode changes.

content/renderer/render_frame_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 2093 matching lines @@
   accessibility_mode_ = new_mode;
   if (render_accessibility_) {
     // Note: this isn't called automatically by the destructor because
     // there'd be no point in calling it in frame teardown, only if there's
     // an accessibility mode change but the frame is persisting.
     render_accessibility_->DisableAccessibility();
 
     delete render_accessibility_;
     render_accessibility_ = NULL;
   }
-  if (accessibility_mode_ == AccessibilityModeOff)
-    return;
 
   if (accessibility_mode_ & AccessibilityModeFlagFullTree)
     render_accessibility_ = new RenderAccessibilityImpl(this);
+
+  FOR_EACH_OBSERVER(RenderFrameObserver, observers_,
+                    AccessibilityModeChanged());
 }
 
 void RenderFrameImpl::OnSnapshotAccessibilityTree(int callback_id) {
   AXContentTreeUpdate response;
   RenderAccessibilityImpl::SnapshotAccessibilityTree(this, &response);
   Send(new AccessibilityHostMsg_SnapshotResponse(
       routing_id_, callback_id, response));
 }
 
 void RenderFrameImpl::OnUpdateOpener(int opener_routing_id) {
@@ skipping 4181 matching lines @@
   // event target. Potentially a Pepper plugin will receive the event.
   // In order to tell whether a plugin gets the last mouse event and which it
   // is, we set |pepper_last_mouse_event_target_| to null here. If a plugin gets
   // the event, it will notify us via DidReceiveMouseEvent() and set itself as
   // |pepper_last_mouse_event_target_|.
   pepper_last_mouse_event_target_ = nullptr;
 #endif
 }
 
 }  // namespace content