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

ppapi/proxy/ppb_video_decoder_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_video_decoder_proxy.h"
 
 #include "base/logging.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "ppapi/proxy/enter_proxy.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
@@ skipping 208 matching lines @@
     return;
 
   // Make the resource and get the API pointer to its interface.
   result->SetHostResource(
       instance, resource_creation.functions()->CreateVideoDecoder(
           instance, graphics_context.host_resource(), profile));
 }
 
 void PPB_VideoDecoder_Proxy::OnMsgDecode(
     const HostResource& decoder,
-    const HostResource& buffer, int32 id, int32 size) {
+    const HostResource& buffer, int32 id, uint32 size) {
   EnterHostFromHostResourceForceCallback<PPB_VideoDecoder_API> enter(
       decoder, callback_factory_,
       &PPB_VideoDecoder_Proxy::SendMsgEndOfBitstreamACKToPlugin, decoder, id);
   if (enter.failed())
     return;
   PP_VideoBitstreamBuffer_Dev bitstream = { id, buffer.host_resource(), size };
   enter.SetResult(enter.object()->Decode(&bitstream, enter.callback()));
 }
 
 void PPB_VideoDecoder_Proxy::OnMsgAssignPictureBuffers(
@@ skipping 69 matching lines @@
 
 void PPB_VideoDecoder_Proxy::OnMsgResetACK(
     const HostResource& decoder, int32_t result) {
   EnterPluginFromHostResource<PPB_VideoDecoder_API> enter(decoder);
   if (enter.succeeded())
     static_cast<VideoDecoder*>(enter.object())->ResetACK(result);
 }
 
 }  // namespace proxy
 }  // namespace ppapi