Add a WebContentsImpl API to snapshot the accessibility tree.

content/browser/web_contents/web_contents_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/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
@@ skipping 704 matching lines @@
 }
 
 void WebContentsImpl::AddAccessibilityMode(AccessibilityMode mode) {
   SetAccessibilityMode(AddAccessibilityModeTo(accessibility_mode_, mode));
 }
 
 void WebContentsImpl::RemoveAccessibilityMode(AccessibilityMode mode) {
   SetAccessibilityMode(RemoveAccessibilityModeFrom(accessibility_mode_, mode));
 }
 
+void WebContentsImpl::RequestAXTreeSnapshot(AXTreeSnapshotCallback callback) {
+  // TODO(dmazzoni): this only returns the accessibility tree from the main
+  // frame and everything in the same site instance.

[Charlie Reis, 2015/04/06 21:56:51]

We should have a bug number for supporting this with OOPIFs.

[dmazzoni, 2015/04/09 18:39:01]

Done.

+  GetMainFrame()->RequestAXTreeSnapshot(callback);
+}
+
 void WebContentsImpl::ClearNavigationTransitionData() {
   FrameTreeNode* node = frame_tree_.root();
   node->render_manager()->ClearNavigationTransitionData();
 }
 
 WebUI* WebContentsImpl::CreateWebUI(const GURL& url) {
   WebUIImpl* web_ui = new WebUIImpl(this);
   WebUIController* controller = WebUIControllerFactoryRegistry::GetInstance()->
       CreateWebUIControllerForURL(web_ui, url);
   if (controller) {
@@ skipping 3851 matching lines @@
   node->render_manager()->ResumeResponseDeferredAtStart();
 }
 
 void WebContentsImpl::SetForceDisableOverscrollContent(bool force_disable) {
   force_disable_overscroll_content_ = force_disable;
   if (view_)
     view_->SetOverscrollControllerEnabled(CanOverscrollContent());
 }
 
 }  // namespace content