Implement the host side of the PPB_PDF proxy.

ppapi/proxy/ppb_image_data_proxy.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/proxy/ppb_image_data_proxy.h"
 
 #include <string.h>  // For memcpy
 
 #include <map>
 #include <vector>
@@ skipping 503 matching lines @@
 #endif
     IPC_MESSAGE_HANDLER(PpapiMsg_PPBImageData_NotifyUnusedImageData,
                         OnPluginMsgNotifyUnusedImageData)
 
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 #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,
                                           PP_Bool init_to_zero,
                                           HostResource* result,
                                           std::string* image_data_desc,
                                           ImageHandle* result_image_handle) {
   *result_image_handle = ImageData::NullHandle();
 
   thunk::EnterResourceCreation enter(instance);
@@ skipping 96 matching lines @@
   // still cached in our process, the proxy still holds a reference so we can
   // remove the one the renderer just sent is. If the proxy no longer holds a
   // reference, we released everything and we should also release the one the
   // renderer just sent us.
   dispatcher()->Send(new PpapiHostMsg_PPBCore_ReleaseResource(
       API_ID_PPB_CORE, old_image_data));
 }
 
 }  // namespace proxy
 }  // namespace ppapi