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

content/common/gpu/media/gpu_video_decode_accelerator.cc

Index: content/common/gpu/media/gpu_video_decode_accelerator.cc
diff --git a/content/common/gpu/media/gpu_video_decode_accelerator.cc b/content/common/gpu/media/gpu_video_decode_accelerator.cc
index 82fd40828546d46ae22bd6c49b53a24a54e1d5e9..6d9b17f4567bf803acb024e8dae842cdafc10227 100644
--- a/content/common/gpu/media/gpu_video_decode_accelerator.cc
+++ b/content/common/gpu/media/gpu_video_decode_accelerator.cc
@@ -163,7 +163,7 @@ void GpuVideoDecodeAccelerator::Initialize(const std::vector<uint32>& configs) {
   omx_decoder->SetEglState(
       gfx::GLSurfaceEGL::GetDisplay(),
       stub_->scheduler()->decoder()->GetGLContext()->GetHandle());
-  video_decode_accelerator_.reset(omx_decoder);
+  video_decode_accelerator_ = omx_decoder;
   video_decode_accelerator_->Initialize(configs);
 #else
   NOTIMPLEMENTED() << "HW video decode acceleration not available.";
@@ -250,11 +250,6 @@ void GpuVideoDecodeAccelerator::NotifyResetDone() {
     LOG(ERROR) << "Send(AcceleratedVideoDecoderHostMsg_ResetDone) failed";
 }
 
-void GpuVideoDecodeAccelerator::NotifyDestroyDone() {
-  if (!Send(new AcceleratedVideoDecoderHostMsg_DestroyDone(host_route_id_)))
-    LOG(ERROR) << "Send(AcceleratedVideoDecoderHostMsg_DestroyDone) failed";
-}
-
 bool GpuVideoDecodeAccelerator::Send(IPC::Message* message) {
   DCHECK(sender_);
   return sender_->Send(message);