Revert "content: convert accessibility notifications to callbacks"

content/browser/accessibility/cross_platform_accessibility_browsertest.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 <string>
 #include <vector>
 
 #include "base/utf_string_conversions.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/public/browser/notification_service.h"
@@ skipping 15 matching lines @@
 namespace content {
 
 class CrossPlatformAccessibilityBrowserTest : public ContentBrowserTest {
  public:
   CrossPlatformAccessibilityBrowserTest() {}
 
   // Tell the renderer to send an accessibility tree, then wait for the
   // notification that it's been received.
   const AccessibilityNodeData& GetAccessibilityNodeDataTree(
       AccessibilityMode accessibility_mode = AccessibilityModeComplete) {
-    scoped_refptr<MessageLoopRunner> loop_runner(new MessageLoopRunner);
+    WindowedNotificationObserver tree_updated_observer(
+        NOTIFICATION_ACCESSIBILITY_LAYOUT_COMPLETE,
+        NotificationService::AllSources());
     RenderWidgetHostView* host_view =
         shell()->web_contents()->GetRenderWidgetHostView();
     RenderWidgetHostImpl* host =
         RenderWidgetHostImpl::From(host_view->GetRenderWidgetHost());
     RenderViewHostImpl* view_host = static_cast<RenderViewHostImpl*>(host);
-    view_host->SetAccessibilityLayoutCompleteCallbackForTesting(
-        loop_runner->QuitClosure());
     view_host->set_save_accessibility_tree_for_testing(true);
     view_host->SetAccessibilityMode(accessibility_mode);
-    loop_runner->Run();
+    tree_updated_observer.Wait();
     return view_host->accessibility_tree_for_testing();
   }
 
   // Make sure each node in the tree has an unique id.
   void RecursiveAssertUniqueIds(
       const AccessibilityNodeData& node, base::hash_set<int>* ids) {
     ASSERT_TRUE(ids->find(node.id) == ids->end());
     ids->insert(node.id);
     for (size_t i = 0; i < node.children.size(); i++)
       RecursiveAssertUniqueIds(node.children[i], ids);
@@ skipping 401 matching lines @@
   const AccessibilityNodeData& tree = GetAccessibilityNodeDataTree();
 
   ASSERT_EQ(1U, tree.children.size());
   const AccessibilityNodeData& textbox = tree.children[0];
 
   EXPECT_EQ(
       true, GetBoolAttr(textbox, AccessibilityNodeData::ATTR_CAN_SET_VALUE));
 }
 
 }  // namespace content