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

content/renderer/pepper_platform_video_decoder_impl.cc

Index: content/renderer/pepper_platform_video_decoder_impl.cc
diff --git a/content/renderer/pepper_platform_video_decoder_impl.cc b/content/renderer/pepper_platform_video_decoder_impl.cc
index 9c8b24721b8ef1c2689893004ce503ce4309ae4f..ac34a3bccff8f98deb38c814fcbf1db8146236e5 100644
--- a/content/renderer/pepper_platform_video_decoder_impl.cc
+++ b/content/renderer/pepper_platform_video_decoder_impl.cc
@@ -20,8 +20,7 @@ PlatformVideoDecoderImpl::PlatformVideoDecoderImpl(
     gpu::CommandBufferHelper* cmd_buffer_helper)
     : client_(client),
       command_buffer_route_id_(command_buffer_route_id),
-      cmd_buffer_helper_(cmd_buffer_helper),
-      decoder_(NULL) {
+      cmd_buffer_helper_(cmd_buffer_helper) {
   DCHECK(client);
 }
 
@@ -133,8 +132,3 @@ void PlatformVideoDecoderImpl::NotifyResetDone() {
   DCHECK_EQ(RenderThread::current()->message_loop(), MessageLoop::current());
   client_->NotifyResetDone();
 }
-
-void PlatformVideoDecoderImpl::NotifyDestroyDone() {
-  DCHECK_EQ(RenderThread::current()->message_loop(), MessageLoop::current());
-  client_->NotifyDestroyDone();
-}