Implement the host side of the PPB_PDF proxy.

ppapi/proxy/pdf_resource.cc

 // Copyright (c) 2013 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/pdf_resource.h"
 
 #include <stdlib.h>
 #include <string.h>
 
 #include "base/command_line.h"
@@ skipping 146 matching lines @@
   IPC::Message reply;
   ResourceMessageReplyParams reply_params;
   int32_t result = GenericSyncCall(
       RENDERER, PpapiHostMsg_PDF_GetResourceImage(image_id, scale), &reply,
       &reply_params);
   if (result != PP_OK)
     return 0;
 
   HostResource resource;
   std::string image_data_desc;
+  int fd;
   if (!UnpackMessage<PpapiPluginMsg_PDF_GetResourceImageReply>(
-      reply, &resource, &image_data_desc)) {
+      reply, &resource, &image_data_desc, &fd)) {
     return 0;
   }
 
   if (resource.is_null() || image_data_desc.size() != sizeof(PP_ImageDataDesc))
     return 0;
 
   // We serialize the PP_ImageDataDesc just by copying to a string.
   PP_ImageDataDesc desc;
   memcpy(&desc, image_data_desc.data(), sizeof(PP_ImageDataDesc));
 
-  base::SharedMemoryHandle handle;
-  if (!reply_params.TakeSharedMemoryHandleAtIndex(0, &handle))
-    return 0;
-  // We always succeed after this point (on non-android platforms, so we don't
-  // have to worry about leaking |handle|.
-
 #if defined(OS_ANDROID)
   // This is compiled into android for tests only.
   return 0;
 #elif defined(OS_WIN) || defined(OS_MACOSX)
+  base::SharedMemoryHandle handle;
+  if (!reply_params.TakeSharedMemoryHandleAtIndex(0, &handle))
+    return 0;
   return (new ImageData(resource, desc, handle))->GetReference();
+#elif defined(OS_LINUX)
+  return (new ImageData(resource, desc, fd))->GetReference();
 #else
-  return (new ImageData(resource, desc, handle.fd))->GetReference();
+#error Not implemented.
 #endif
 }
 
 PP_Resource PDFResource::GetResourceImage(PP_ResourceImage image_id) {
   return GetResourceImageForScale(image_id, 1.0f);
 }
 
 }  // namespace proxy
 }  // namespace ppapi