Fix some types at the IPC layer. Sizes should be unsigned.

ppapi/proxy/ppb_video_decoder_proxy.h

 // Copyright (c) 2011 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.
 
 #ifndef PPAPI_PROXY_PPB_VIDEO_DECODER_PROXY_H_
 #define PPAPI_PROXY_PPB_VIDEO_DECODER_PROXY_H_
 
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/proxy/interface_proxy.h"
 #include "ppapi/proxy/proxy_completion_callback_factory.h"
@@ skipping 22 matching lines @@
 
  private:
   // Message handlers in the renderer process to receive messages from the
   // plugin process.
   void OnMsgCreate(PP_Instance instance,
                    const ppapi::HostResource& graphics_context,
                    PP_VideoDecoder_Profile profile,
                    ppapi::HostResource* result);
   void OnMsgDecode(
       const ppapi::HostResource& decoder,
-      const ppapi::HostResource& buffer, int32 id, int32 size);
+      const ppapi::HostResource& buffer, int32 id, uint32 size);
   void OnMsgAssignPictureBuffers(
       const ppapi::HostResource& decoder,
       const std::vector<PP_PictureBuffer_Dev>& buffers);
   void OnMsgReusePictureBuffer(
       const ppapi::HostResource& decoder,
       int32 picture_buffer_id);
   void OnMsgFlush(const ppapi::HostResource& decoder);
   void OnMsgReset(const ppapi::HostResource& decoder);
   void OnMsgDestroy(const ppapi::HostResource& decoder);
 
@@ skipping 15 matching lines @@
 
   ProxyCompletionCallbackFactory<PPB_VideoDecoder_Proxy> callback_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PPB_VideoDecoder_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPB_VIDEO_DECODER_PROXY_H_