Support exposing Mojo services between render frames, render threads, and their respective hosts.

content/public/browser/render_frame_host.h

Index: content/public/browser/render_frame_host.h
diff --git a/content/public/browser/render_frame_host.h b/content/public/browser/render_frame_host.h
index ac6ba5aa8d7daad53e989f6e029d98d86781c65e..31f4d8df99a1db8dd24eadb78b4086e534675a50 100644
--- a/content/public/browser/render_frame_host.h
+++ b/content/public/browser/render_frame_host.h
@@ -21,6 +21,7 @@ class Value;
 namespace content {
 class RenderProcessHost;
 class RenderViewHost;
+class ServiceRegistry;
 class SiteInstance;
 
 // The interface provides a communication conduit with a frame in the renderer.
@@ -74,6 +75,9 @@ class CONTENT_EXPORT RenderFrameHost : public IPC::Listener,
   // Temporary until we get rid of RenderViewHost.
   virtual RenderViewHost* GetRenderViewHost() = 0;
 
+  // Returns the ServiceRegistry for this frame.
+  virtual ServiceRegistry* GetServiceRegistry() = 0;
+
  private:
   // This interface should only be implemented inside content.
   friend class RenderFrameHostImpl;