Remove NOTIFICATION_WEB_CONTENTS_VISIBILITY_CHANGED from browser plugin.

content/browser/browser_plugin/test_browser_plugin_guest.h

Index: content/browser/browser_plugin/test_browser_plugin_guest.h
diff --git a/content/browser/browser_plugin/test_browser_plugin_guest.h b/content/browser/browser_plugin/test_browser_plugin_guest.h
index 7fccb00238852e4361b72c129d40cca6296503ea..dd8952805d3938a2f47b08df6006eb16241e13a1 100644
--- a/content/browser/browser_plugin/test_browser_plugin_guest.h
+++ b/content/browser/browser_plugin/test_browser_plugin_guest.h
@@ -27,11 +27,6 @@ class TestBrowserPluginGuest : public BrowserPluginGuest {
 
   WebContentsImpl* web_contents() const;
 
-  // NotificationObserver method override.
-  virtual void Observe(int type,
-                       const NotificationSource& source,
-                       const NotificationDetails& details) OVERRIDE;
-
   // Overridden methods from BrowserPluginGuest to intercept in test objects.
   virtual void RenderProcessGone(base::TerminationStatus status) OVERRIDE;
   virtual void OnHandleInputEvent(int instance_id,
@@ -43,6 +38,9 @@ class TestBrowserPluginGuest : public BrowserPluginGuest {
       const BrowserPluginHostMsg_ResizeGuest_Params& params) OVERRIDE;
   virtual void DidStopLoading(RenderViewHost* render_view_host) OVERRIDE;
 
+  // Overridden from WebContentsObserver.
+  virtual void WasHidden() OVERRIDE;
+
   // Test utilities to wait for a event we are interested in.
   // Waits until UpdateRect message is sent from the guest, meaning it is
   // ready/rendered.