Fix RenderFrameHostChanged WebContentsObserver methods

content/browser/frame_host/render_frame_host_manager.h

Index: content/browser/frame_host/render_frame_host_manager.h
diff --git a/content/browser/frame_host/render_frame_host_manager.h b/content/browser/frame_host/render_frame_host_manager.h
index 15338be2d0de70f6d680a0daf3b0359aa460b58d..073908ad44cf1b497b062b96ec6b18ebf4529ef9 100644
--- a/content/browser/frame_host/render_frame_host_manager.h
+++ b/content/browser/frame_host/render_frame_host_manager.h
@@ -137,6 +137,11 @@ class CONTENT_EXPORT RenderFrameHostManager : public NotificationObserver {
     virtual void NotifySwappedFromRenderManager(RenderFrameHost* old_host,
                                                 RenderFrameHost* new_host,
                                                 bool is_main_frame) = 0;
+    // TODO(nasko): This should be removed once extensions no longer use
+    // NotificationService. See https://crbug.com/462682.
+    virtual void NotifyMainFrameSwappedFromRenderManager(
+        RenderViewHost* old_host,
+        RenderViewHost* new_host) = 0;
     virtual NavigationControllerImpl&
         GetControllerForRenderManager() = 0;