Pass RenderFrameHost to WebContentObservers' message handlers

extensions/browser/extension_function.cc

Index: extensions/browser/extension_function.cc
diff --git a/extensions/browser/extension_function.cc b/extensions/browser/extension_function.cc
index 470ae55635d914af573e738d14090522f04ea578..270f9074519138e4ced1497963eb1c6ef3923010 100644
--- a/extensions/browser/extension_function.cc
+++ b/extensions/browser/extension_function.cc
@@ -130,6 +130,16 @@ class UIThreadExtensionFunction::RenderHostTracker
     function_->SetRenderFrameHost(NULL);
   }
 
+  virtual bool OnMessageReceived(
+      const IPC::Message& message,
+      content::RenderFrameHost* render_frame_host) OVERRIDE {
+    DCHECK(render_frame_host);
+    if (render_frame_host == function_->render_frame_host())
+      return function_->OnMessageReceived(message);
+    else
+      return false;
+  }
+
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE {
     return function_->OnMessageReceived(message);
   }