Switch ContentSettingsObserver to be a RenderFrameObserver instead of a RenderViewObserver

content/browser/frame_host/render_frame_host_delegate.h

Index: content/browser/frame_host/render_frame_host_delegate.h
===================================================================
--- content/browser/frame_host/render_frame_host_delegate.h	(revision 240912)
+++ content/browser/frame_host/render_frame_host_delegate.h	(working copy)
@@ -13,6 +13,7 @@
 
 namespace content {
 class RenderFrameHost;
+class WebContents;
 
 // An interface implemented by an object interested in knowing about the state
 // of the RenderFrameHost.
@@ -28,6 +29,10 @@
   // Informs the delegate whenever a RenderFrameHost is deleted.
   virtual void RenderFrameDeleted(RenderFrameHost* render_frame_host) {}
 
+  // Return this object cast to a WebContents, if it is one. If the object is
+  // not a WebContents, returns NULL.

[nasko, 2013/12/16 19:47:37]

RenderViewHostDelegate has(had?) identical method that was marked deprecated and
not to be used. Should we be adding this if we wanted to remove the other such
method?

[jam, 2013/12/16 20:26:48]

I had added that comment, but afterwards realized that it's not possible to
remove.

As for this method, I had started a discussion about this on site-isolation's
mailing list but it turned private between ajwong and me at the end; where he
saw that it was necessary to have this method. The reason is that we can
sometimes be on a non-UI thread with only a render_frame and render_process IDs,
and we need to get to a WebContents. as in this change. In that case, there's no
other way to get to WC except through the RF's delegate

+  virtual WebContents* GetAsWebContents();
+
  protected:
   virtual ~RenderFrameHostDelegate() {}
 };