Enable fire-and-forget Destroy of HW video decoder, and misc other improvements.

ppapi/cpp/dev/video_decoder_client_dev.h

Index: ppapi/cpp/dev/video_decoder_client_dev.h
diff --git a/ppapi/cpp/dev/video_decoder_client_dev.h b/ppapi/cpp/dev/video_decoder_client_dev.h
index 776d54baebd1f202e92ca0769b4c211aa447727e..d1c57427d7fac87974de0ae071370592e979629f 100644
--- a/ppapi/cpp/dev/video_decoder_client_dev.h
+++ b/ppapi/cpp/dev/video_decoder_client_dev.h
@@ -24,29 +24,23 @@ class VideoDecoderClient_Dev {
 
   // Callback to provide buffers for the decoded output pictures.
   virtual void ProvidePictureBuffers(
-      VideoDecoder_Dev decoder,
       uint32_t req_num_of_bufs,
       struct PP_Size dimensions,
       enum PP_PictureBufferType_Dev type) = 0;
 
-  // Callback for decoder to delivered unneeded picture buffers back to the
+  // Callback for decoder to deliver unneeded picture buffers back to the
   // plugin.
-  virtual void DismissPictureBuffer(
-      VideoDecoder_Dev decoder,
-      int32_t picture_buffer_id) = 0;
+  virtual void DismissPictureBuffer(int32_t picture_buffer_id) = 0;
 
   // Callback to deliver decoded pictures ready to be displayed.
-  virtual void PictureReady(
-      VideoDecoder_Dev decoder,
-      const PP_Picture_Dev& picture) = 0;
+  virtual void PictureReady(const PP_Picture_Dev& picture) = 0;
 
   // Callback to notify that decoder has decoded end of stream marker and has
   // outputted all displayable pictures.
-  virtual void EndOfStream(VideoDecoder_Dev decoder) = 0;
+  virtual void EndOfStream() = 0;
 
   // Callback to notify about decoding errors.
-  virtual void NotifyError(
-      VideoDecoder_Dev decoder, PP_VideoDecodeError_Dev error) = 0;
+  virtual void NotifyError(PP_VideoDecodeError_Dev error) = 0;
 
  private:
   Instance* associated_instance_;