Improve comments on WebContentsObserver RenderFrame* methods and rename.

content/public/browser/web_contents.h

Index: content/public/browser/web_contents.h
diff --git a/content/public/browser/web_contents.h b/content/public/browser/web_contents.h
index 49ea4cde75b80a1fb743ad92a9b429d356f05365..ed0092f988c0d2a11b67f971d65a14db588e5aa1 100644
--- a/content/public/browser/web_contents.h
+++ b/content/public/browser/web_contents.h
@@ -192,6 +192,9 @@ class WebContents : public PageNavigator,
   virtual RenderFrameHost* GetFocusedFrame() = 0;
 
   // Calls |on_frame| for each frame in the currently active view.
+  // Note: The RenderFrameHost parameter is not guaranteed to have a live
+  // RenderFrame counterpart in the renderer process. Callbacks should check
+  // IsRenderFrameLive, as sending IPC messages to it will fail silently.

[Charlie Reis, 2015/01/22 00:17:15]

nit: to it in this case

[nasko, 2015/01/22 00:27:23]

Done.

   virtual void ForEachFrame(
       const base::Callback<void(RenderFrameHost*)>& on_frame) = 0;