Start splitting out WebUI into an implementation class and an interface that each page implements...

chrome/browser/ui/webui/chromeos/mobile_setup_ui.h

Index: chrome/browser/ui/webui/chromeos/mobile_setup_ui.h
===================================================================
--- chrome/browser/ui/webui/chromeos/mobile_setup_ui.h	(revision 117388)
+++ chrome/browser/ui/webui/chromeos/mobile_setup_ui.h	(working copy)
@@ -7,15 +7,16 @@
 #pragma once
 
 #include "content/browser/webui/web_ui.h"
+#include "content/public/browser/web_ui_controller.h"
 
 // A custom WebUI that defines datasource for mobile setup registration page
 // that is used in Chrome OS activate modem and perform plan subscription tasks.
-class MobileSetupUI : public WebUI {
+class MobileSetupUI : public WebUI, public content::WebUIController {
  public:
   explicit MobileSetupUI(content::WebContents* contents);
 
  private:
-  // WebUI overrides.
+  // WebUIController overrides.
   virtual void RenderViewCreated(RenderViewHost* render_view_host) OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(MobileSetupUI);