Implement the host side of the PPB_PDF proxy.

ppapi/proxy/ppb_image_data_proxy.cc

Index: ppapi/proxy/ppb_image_data_proxy.cc
diff --git a/ppapi/proxy/ppb_image_data_proxy.cc b/ppapi/proxy/ppb_image_data_proxy.cc
index b2ede29954ed210fece2131bc1fbd00abca54590..a5647a3e73d4b901b442ba7f822a72025a9e8977 100644
--- a/ppapi/proxy/ppb_image_data_proxy.cc
+++ b/ppapi/proxy/ppb_image_data_proxy.cc
@@ -521,6 +521,8 @@ bool PPB_ImageData_Proxy::OnMessageReceived(const IPC::Message& msg) {
 }
 
 #if !defined(OS_NACL)
+// TODO(raymes): Do we leak resources in these Create functions if the code
+// fails to return a handle to the plugin?

[yzshen1, 2013/04/03 18:32:39]

The resource is passed to the plugin side as HostResource |result|. As long as
we create a plugin-side resource object using this HostResource, it is managed.
It seems even if the code fails to return a handle, it is okay. But if
|image_data_desc| has wrong size, it will leak.

[raymes, 2013/04/03 23:18:21]

ok I removed the todo

 void PPB_ImageData_Proxy::OnHostMsgCreate(PP_Instance instance,
                                           int32_t format,
                                           const PP_Size& size,