PPAPI: Make blocking completion callbacks work.

ppapi/thunk/ppb_video_decoder_api.h

Index: ppapi/thunk/ppb_video_decoder_api.h
diff --git a/ppapi/thunk/ppb_video_decoder_api.h b/ppapi/thunk/ppb_video_decoder_api.h
index e17d22b88fbea56756cf9dc2c2e329ac4f16ce27..96488d65dc225bb8534611798bda580b7b35d97f 100644
--- a/ppapi/thunk/ppb_video_decoder_api.h
+++ b/ppapi/thunk/ppb_video_decoder_api.h
@@ -6,6 +6,7 @@
 #define PPAPI_THUNK_VIDEO_DECODER_API_H_
 
 #include "ppapi/c/dev/ppb_video_decoder_dev.h"
+#include "ppapi/shared_impl/api_callback_type.h"
 
 namespace ppapi {
 namespace thunk {
@@ -15,12 +16,12 @@ class PPB_VideoDecoder_API {
   virtual ~PPB_VideoDecoder_API() {}
 
   virtual int32_t Decode(const PP_VideoBitstreamBuffer_Dev* bitstream_buffer,
-                         PP_CompletionCallback callback) = 0;
+                         ApiCallbackType callback) = 0;
   virtual void AssignPictureBuffers(uint32_t no_of_buffers,
                                     const PP_PictureBuffer_Dev* buffers) = 0;
   virtual void ReusePictureBuffer(int32_t picture_buffer_id) = 0;
-  virtual int32_t Flush(PP_CompletionCallback callback) = 0;
-  virtual int32_t Reset(PP_CompletionCallback callback) = 0;
+  virtual int32_t Flush(ApiCallbackType callback) = 0;
+  virtual int32_t Reset(ApiCallbackType callback) = 0;
   virtual void Destroy() = 0;
 };