Gracefully handle multiple Flush/Reset/Decode with same id

webkit/plugins/ppapi/ppb_video_decoder_impl.cc

 // 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.
 
 #include "webkit/plugins/ppapi/ppb_video_decoder_impl.h"
 
 #include <string>
 
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ skipping 86 matching lines @@
 
   EnterResourceNoLock<PPB_Buffer_API> enter(bitstream_buffer->data, true);
   if (enter.failed())
     return PP_ERROR_FAILED;
 
   PPB_Buffer_Impl* buffer = static_cast<PPB_Buffer_Impl*>(enter.object());
   media::BitstreamBuffer decode_buffer(
       bitstream_buffer->id,
       buffer->shared_memory()->handle(),
       static_cast<size_t>(bitstream_buffer->size));
-  SetBitstreamBufferCallback(bitstream_buffer->id, callback);
+  if (!SetBitstreamBufferCallback(bitstream_buffer->id, callback))
+    return PP_ERROR_BADARGUMENT;
 
   FlushCommandBuffer();
   platform_video_decoder_->Decode(decode_buffer);
   return PP_OK_COMPLETIONPENDING;
 }
 
 void PPB_VideoDecoder_Impl::AssignPictureBuffers(
     uint32_t no_of_buffers,
     const PP_PictureBuffer_Dev* buffers) {
   if (!platform_video_decoder_)
@@ skipping 18 matching lines @@
     return;
 
   FlushCommandBuffer();
   platform_video_decoder_->ReusePictureBuffer(picture_buffer_id);
 }
 
 int32_t PPB_VideoDecoder_Impl::Flush(PP_CompletionCallback callback) {
   if (!platform_video_decoder_)
     return PP_ERROR_BADRESOURCE;
 
-  SetFlushCallback(callback);
+  if (!SetFlushCallback(callback))
+    return PP_ERROR_INPROGRESS;
 
   FlushCommandBuffer();
   platform_video_decoder_->Flush();
   return PP_OK_COMPLETIONPENDING;
 }
 
 int32_t PPB_VideoDecoder_Impl::Reset(PP_CompletionCallback callback) {
   if (!platform_video_decoder_)
     return PP_ERROR_BADRESOURCE;
 
-  SetResetCallback(callback);
+  if (!SetResetCallback(callback))
+    return PP_ERROR_INPROGRESS;
 
   FlushCommandBuffer();
   platform_video_decoder_->Reset();
   return PP_OK_COMPLETIONPENDING;
 }
 
 void PPB_VideoDecoder_Impl::Destroy() {
   if (!platform_video_decoder_)
     return;
 
@@ skipping 78 matching lines @@
 void PPB_VideoDecoder_Impl::AddRefResource(PP_Resource resource) {
   ResourceTracker::Get()->AddRefResource(resource);
 }
 
 void PPB_VideoDecoder_Impl::UnrefResource(PP_Resource resource) {
   ResourceTracker::Get()->UnrefResource(resource);
 }
 
 }  // namespace ppapi
 }  // namespace webkit