gpu: reference target surfaces through a globally unique surface id.

content/public/browser/render_process_host.h

Index: content/public/browser/render_process_host.h
diff --git a/content/public/browser/render_process_host.h b/content/public/browser/render_process_host.h
index 68ed03280e33d5441e351fe8ca05a36c395751b3..e3ada3226eb5a477e52136b4c7a4829691aaf2dd 100644
--- a/content/public/browser/render_process_host.h
+++ b/content/public/browser/render_process_host.h
@@ -122,14 +122,6 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Message::Sender,
   // still owns the returned DIB.
   virtual TransportDIB* GetTransportDIB(TransportDIB::Id dib_id) = 0;
 
-  // RenderWidgetHost / compositing surface mapping functions ------------------
-
-  // Set a mapping from a RenderWidgetHost to a compositing surface. Pass a null
-  // handle to remove the mapping.
-  virtual void SetCompositingSurface(
-      int render_widget_id,
-      gfx::PluginWindowHandle compositing_surface) = 0;
-
   // Returns the user browser context associated with this renderer process.
   virtual content::BrowserContext* GetBrowserContext() const = 0;