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 79731e6251e97edc84ca5b4468805bc6076fbc01..76d78b151812eed38c7090878d7238ff45ae96fb 100644
--- a/ppapi/host/ppapi_host.h
+++ b/ppapi/host/ppapi_host.h
@@ -6,6 +6,7 @@
 #define PPAPI_HOST_PPAPI_HOST_H_
 
 #include <map>
+#include <set>
 
 #include "base/compiler_specific.h"
 #include "base/memory/linked_ptr.h"
@@ -66,6 +67,9 @@ 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;
 
@@ -86,9 +90,6 @@ 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_;