content: convert accessibility notifications to observer usage

content/browser/accessibility/cross_platform_accessibility_browsertest.cc

Index: content/browser/accessibility/cross_platform_accessibility_browsertest.cc
diff --git a/content/browser/accessibility/cross_platform_accessibility_browsertest.cc b/content/browser/accessibility/cross_platform_accessibility_browsertest.cc
index 7135283930cfb1e5c79fd191bd30d1d112e5dcea..d964a3ee4a44ad3839968848f32e1bf8c18fd353 100644
--- a/content/browser/accessibility/cross_platform_accessibility_browsertest.cc
+++ b/content/browser/accessibility/cross_platform_accessibility_browsertest.cc
@@ -9,6 +9,7 @@
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
+#include "content/public/browser/render_view_host_observer.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/test/test_utils.h"
@@ -25,6 +26,28 @@
 
 namespace content {
 
+namespace {
+
+class TestRenderViewHostObserver : public RenderViewHostObserver {
+ public:
+  explicit TestRenderViewHostObserver(RenderViewHost* rvh,
+                                      const base::Closure& callback)
+      : RenderViewHostObserver(rvh),
+        callback_(callback) {
+  }
+
+  virtual void AccessibilityLayoutComplete() OVERRIDE {
+    callback_.Run();
+  }
+
+ private:
+  base::Closure callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestRenderViewHostObserver);
+};
+
+}  // namespace
+
 class CrossPlatformAccessibilityBrowserTest : public ContentBrowserTest {
  public:
   CrossPlatformAccessibilityBrowserTest() {}
@@ -33,17 +56,16 @@ class CrossPlatformAccessibilityBrowserTest : public ContentBrowserTest {
   // notification that it's been received.
   const AccessibilityNodeData& GetAccessibilityNodeDataTree(
       AccessibilityMode accessibility_mode = AccessibilityModeComplete) {
-    WindowedNotificationObserver tree_updated_observer(
-        NOTIFICATION_ACCESSIBILITY_LAYOUT_COMPLETE,
-        NotificationService::AllSources());
+    scoped_refptr<MessageLoopRunner> loop_runner(new MessageLoopRunner);
     RenderWidgetHostView* host_view =
         shell()->web_contents()->GetRenderWidgetHostView();
     RenderWidgetHostImpl* host =
         RenderWidgetHostImpl::From(host_view->GetRenderWidgetHost());
     RenderViewHostImpl* view_host = static_cast<RenderViewHostImpl*>(host);
+    TestRenderViewHostObserver observer(view_host, loop_runner->QuitClosure());
     view_host->set_save_accessibility_tree_for_testing(true);
     view_host->SetAccessibilityMode(accessibility_mode);
-    tree_updated_observer.Wait();
+    loop_runner->Run();
     return view_host->accessibility_tree_for_testing();
   }