Revert of Re-land: Fix loading accessibility tree for child frame that's already loaded.

content/renderer/accessibility/render_accessibility_impl.cc

 // Copyright (c) 2012 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/accessibility/render_accessibility_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <queue>
@@ skipping 57 matching lines @@
 RenderAccessibilityImpl::RenderAccessibilityImpl(RenderFrameImpl* render_frame)
     : RenderFrameObserver(render_frame),
       render_frame_(render_frame),
       tree_source_(render_frame),
       serializer_(&tree_source_),
       pdf_tree_source_(nullptr),
       last_scroll_offset_(gfx::Size()),
       ack_pending_(false),
       reset_token_(0),
       weak_factory_(this) {
+  // There's only one AXObjectCache for the root of a local frame tree,
+  // so if this frame's parent is local we can safely do nothing.
+  if (render_frame_ &&
+      render_frame_->GetWebFrame() &&
+      render_frame_->GetWebFrame()->parent() &&
+      render_frame_->GetWebFrame()->parent()->isWebLocalFrame()) {
+    return;
+  }
+
   WebView* web_view = render_frame_->GetRenderView()->GetWebView();
   WebSettings* settings = web_view->settings();
   settings->setAccessibilityEnabled(true);
 
 #if defined(OS_ANDROID)
   // Password values are only passed through on Android.
   settings->setAccessibilityPasswordValuesEnabled(true);
 #endif
 
 #if !defined(OS_ANDROID)
@@ skipping 592 matching lines @@
       size_t new_count = pdf_update.nodes.size();
       update->nodes.resize(old_count + new_count);
       for (size_t i = 0; i < new_count; ++i)
         update->nodes[old_count + i] = pdf_update.nodes[i];
       break;
     }
   }
 }
 
 }  // namespace content