content: convert accessibility notifications to observer usage

content/browser/renderer_host/render_view_host_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 404 matching lines @@
                        const std::string& frame_tree);
 
   void set_save_accessibility_tree_for_testing(bool save) {
     save_accessibility_tree_for_testing_ = save;
   }
 
   const AccessibilityNodeData& accessibility_tree_for_testing() {
     return accessibility_tree_;
   }
 
+  // Add/remove accessibility callbacks (only for testing).
+  void AddAccessibilityLayoutCompleteCallbackForTesting(
+      const base::Closure& callback);
+  void RemoveAccessibilityLayoutCompleteCallbackForTesting(
+      const base::Closure& callback);
+  void AddAccessibilityLoadCompleteCallbackForTesting(
+      const base::Closure& callback);
+  void RemoveAccessibilityLoadCompleteCallbackForTesting(
+      const base::Closure& callback);
+
   bool is_waiting_for_unload_ack_for_testing() {
     return is_waiting_for_unload_ack_;
   }
 
   // Checks that the given renderer can request |url|, if not it sets it to
   // about:blank.
   // empty_allowed must be set to false for navigations for security reasons.
   static void FilterURL(ChildProcessSecurityPolicyImpl* policy,
                         const RenderProcessHost* process,
                         bool empty_allowed,
@@ skipping 210 matching lines @@
   // the case of a cross-site transition ( = true).
   bool unload_ack_is_for_cross_site_transition_;
 
   bool are_javascript_messages_suppressed_;
 
   // The mapping of pending javascript calls created by
   // ExecuteJavascriptInWebFrameCallbackResult and their corresponding
   // callbacks.
   std::map<int, JavascriptResultCallback> javascript_callbacks_;
 
+  // Accessibility callbacks.
+  std::vector<base::Closure> accessibility_layout_callbacks_;

[dmazzoni, 2013/02/12 16:00:52]

I can't imagine we'll ever need more than one callback for tests. Just one of
each type should be fine, and the current usage pattern where it's used only to
block until the callback occurs should be fine.

How about if the callback is just called once and then deleted? Change it to:

SetOneTimeAccessibilityLoadCompleteCallbackForTesting()

...with no vector needed, and no Remove method needed.

[jam, 2013/02/12 17:48:18]

+1

+  std::vector<base::Closure> accessibility_load_callbacks_;
+
   // True if the render view can be shut down suddenly.
   bool sudden_termination_allowed_;
 
   // The session storage namespace to be used by the associated render view.
   scoped_refptr<SessionStorageNamespaceImpl> session_storage_namespace_;
 
   // Whether the accessibility tree should be saved, for unit testing.
   bool save_accessibility_tree_for_testing_;
 
   // A JSON serialized representation of the frame tree for the current document
@@ skipping 27 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostImpl);
 };
 
 #if defined(COMPILER_MSVC)
 #pragma warning(pop)
 #endif
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_IMPL_H_