Implement proper synchronization between HW video decode IPC and CommandBuffer.

webkit/plugins/ppapi/ppb_video_decoder_impl.cc

Index: webkit/plugins/ppapi/ppb_video_decoder_impl.cc
diff --git a/webkit/plugins/ppapi/ppb_video_decoder_impl.cc b/webkit/plugins/ppapi/ppb_video_decoder_impl.cc
index d1e41d46a6425247c9c8611804139ab0b9cc82ae..6198bf3bac65c3791a65e37ec9cf91c9c6ecad29 100644
--- a/webkit/plugins/ppapi/ppb_video_decoder_impl.cc
+++ b/webkit/plugins/ppapi/ppb_video_decoder_impl.cc
@@ -8,6 +8,7 @@
 
 #include "base/logging.h"
 #include "base/message_loop.h"
+#include "gpu/command_buffer/client/gles2_implementation.h"
 #include "media/video/picture.h"
 #include "ppapi/c/dev/pp_video_dev.h"
 #include "ppapi/c/dev/ppb_video_decoder_dev.h"
@@ -127,7 +128,7 @@ int32_t PPB_VideoDecoder_Impl::Initialize(
 
   platform_video_decoder_.reset(
       instance()->delegate()->CreateVideoDecoder(
-          this, command_buffer_route_id));
+          this, command_buffer_route_id, context3d->gles2_impl()->helper()));

[piman, 2011/06/28 01:19:22]

FYI, context3d->gles2_impl() will be NULL in out-of-process (see comments in
other file).

Also, unrelated to this CL, but FYI, you can have a race condition with
command_buffer_route_id. It is really relative to the GpuChannelHost. If the GPU
process crashes/gets killed between the GetCommandBufferRouteId (or even before
that) and the time you create the video decoder, you will spawn a new GPU
process and try to reference a route ID that doesn't exist (or worse, a valid
one but not the one you want). Definitely worth at least a TODO (and a bug).

[Ami GONE FROM CHROMIUM, 2011/06/28 21:00:53]

Done.

 
   if (!platform_video_decoder_.get())
     return PP_ERROR_FAILED;
@@ -160,10 +161,8 @@ int32_t PPB_VideoDecoder_Impl::Decode(
   CHECK(bitstream_buffer_callbacks_.insert(std::make_pair(
       bitstream_buffer->id, callback)).second);
 
-  if (platform_video_decoder_->Decode(decode_buffer))
-    return PP_OK_COMPLETIONPENDING;
-  else
-    return PP_ERROR_FAILED;
+  platform_video_decoder_->Decode(decode_buffer);
+  return PP_OK_COMPLETIONPENDING;
 }
 
 void PPB_VideoDecoder_Impl::AssignGLESBuffers(
@@ -223,10 +222,8 @@ int32_t PPB_VideoDecoder_Impl::Flush(PP_CompletionCallback callback) {
   // TODO(vmr): Check for current flush/abort operations.
   flush_callback_ = callback;
 
-  if (platform_video_decoder_->Flush())
-    return PP_OK_COMPLETIONPENDING;
-  else
-    return PP_ERROR_FAILED;
+  platform_video_decoder_->Flush();
+  return PP_OK_COMPLETIONPENDING;
 }
 
 int32_t PPB_VideoDecoder_Impl::Abort(PP_CompletionCallback callback) {
@@ -237,10 +234,8 @@ int32_t PPB_VideoDecoder_Impl::Abort(PP_CompletionCallback callback) {
   // TODO(vmr): Check for current flush/abort operations.
   abort_callback_ = callback;
 
-  if (platform_video_decoder_->Abort())
-    return PP_OK_COMPLETIONPENDING;
-  else
-    return PP_ERROR_FAILED;
+  platform_video_decoder_->Abort();
+  return PP_OK_COMPLETIONPENDING;
 }
 
 void PPB_VideoDecoder_Impl::ProvidePictureBuffers(