Remove implicit conversions from scoped_refptr to T* in media/

media/filters/vpx_video_decoder.cc

Index: media/filters/vpx_video_decoder.cc
diff --git a/media/filters/vpx_video_decoder.cc b/media/filters/vpx_video_decoder.cc
index ec902b888f8d5a8dc3a489330098c9355acaed4d..cb652c0152583e29d05fa6f4c26b3052d02c78c9 100644
--- a/media/filters/vpx_video_decoder.cc
+++ b/media/filters/vpx_video_decoder.cc
@@ -267,7 +267,7 @@ bool VpxVideoDecoder::ConfigureDecoder(const VideoDecoderConfig& config) {
     if (vpx_codec_set_frame_buffer_functions(vpx_codec_,
                                              &MemoryPool::GetVP9FrameBuffer,
                                              &MemoryPool::ReleaseVP9FrameBuffer,
-                                             memory_pool_)) {
+                                             memory_pool_.get())) {

[ddorwin, 2014/08/25 21:26:40]

This parameter is "Callback's private data".
I didn't verify that the member outlives this use.

[dcheng, 2014/08/25 21:33:25]

It's worth noting this was already using the implicit conversion operator
before. Making this explicit doesn't make it any less memory-safe--the code in
question must be keeping it alive some other way, or this is an error (since the
callback parameter is a void*).

[Tom Finegan, 2014/08/26 00:26:11]

caveat: I did not write or review this part of VpxVideoDecoder, but...

Libvpx is the one using that void* for the static methods in VpxVideoDecoder's
MemoryPool class. VpxVideoDecoder is holding the reference for libvpx because
libvpx doesn't know anything about scoped_refptrs. VpxVideoDecoder is nulling it
out in CloseDecoder()(thus releasing the reference), but only after libvpx has
been shut down. This should be safe because after that point libvpx will no
longer be alive to call GetVP9FrameBuffer() or ReleaseVP9FrameBuffer().

Assuming that's what you're asking, anyway.

       LOG(ERROR) << "Failed to configure external buffers.";
       return false;
     }
@@ -333,7 +333,7 @@ void VpxVideoDecoder::DecodeBuffer(const scoped_refptr<DecoderBuffer>& buffer) {
   DCHECK_NE(state_, kDecodeFinished);
   DCHECK_NE(state_, kError);
   DCHECK(!decode_cb_.is_null());
-  DCHECK(buffer);
+  DCHECK(buffer.get());
 
   // Transition to kDecodeFinished on the first end of stream buffer.
   if (state_ == kNormal && buffer->end_of_stream()) {
@@ -351,7 +351,7 @@ void VpxVideoDecoder::DecodeBuffer(const scoped_refptr<DecoderBuffer>& buffer) {
 
   base::ResetAndReturn(&decode_cb_).Run(kOk);
 
-  if (video_frame)
+  if (video_frame.get())
     output_cb_.Run(video_frame);
 }
 
@@ -449,7 +449,7 @@ void VpxVideoDecoder::CopyVpxImageTo(const vpx_image* vpx_image,
 
   gfx::Size size(vpx_image->d_w, vpx_image->d_h);
 
-  if (!vpx_codec_alpha_ && memory_pool_) {
+  if (!vpx_codec_alpha_ && memory_pool_.get()) {
     *video_frame = VideoFrame::WrapExternalYuvData(
         codec_format,
         size, gfx::Rect(size), config_.natural_size(),