Migrate Graphics2D to new design.

ppapi/host/ppapi_host.h

Index: ppapi/host/ppapi_host.h
diff --git a/ppapi/host/ppapi_host.h b/ppapi/host/ppapi_host.h
index 3597093b9a3e8a792e7256f93b1f5195bb0305ed..7210b81da10369851075f6e0781d68c2ca85af47 100644
--- a/ppapi/host/ppapi_host.h
+++ b/ppapi/host/ppapi_host.h
@@ -69,6 +69,9 @@ class PPAPI_HOST_EXPORT PpapiHost : public IPC::Sender, public IPC::Listener {
   // ownership of the pointer.
   void AddInstanceMessageFilter(scoped_ptr<InstanceMessageFilter> filter);
 
+  // Returns null if the resource doesn't exist.
+  host::ResourceHost* GetResourceHost(PP_Resource resource) const;
+
  private:
   friend class InstanceMessageFilter;
 
@@ -89,9 +92,6 @@ class PPAPI_HOST_EXPORT PpapiHost : public IPC::Sender, public IPC::Listener {
                                 const IPC::Message& nested_msg);
   void OnHostMsgResourceDestroyed(PP_Resource resource);
 
-  // Returns null if the resource doesn't exist.
-  host::ResourceHost* GetResourceHost(PP_Resource resource);
-
   // Non-owning pointer.
   IPC::Sender* sender_;