Fix webrtc HW encode deadlock scenarios.

content/renderer/media/rtc_video_encoder.cc

Index: content/renderer/media/rtc_video_encoder.cc
diff --git a/content/renderer/media/rtc_video_encoder.cc b/content/renderer/media/rtc_video_encoder.cc
index 1a4efcdc4e8220c4b630dde9919d6f3832031c38..bc40f4508891a041da903ac22f9c3b7c0b098442 100644
--- a/content/renderer/media/rtc_video_encoder.cc
+++ b/content/renderer/media/rtc_video_encoder.cc
@@ -250,7 +250,6 @@ void RTCVideoEncoder::Impl::Destroy() {
 void RTCVideoEncoder::Impl::NotifyInitializeDone() {
   DVLOG(3) << "Impl::NotifyInitializeDone()";
   DCHECK(thread_checker_.CalledOnValidThread());
-  SignalAsyncWaiter(WEBRTC_VIDEO_CODEC_OK);
 }
 
 void RTCVideoEncoder::Impl::RequireBitstreamBuffers(
@@ -298,6 +297,7 @@ void RTCVideoEncoder::Impl::RequireBitstreamBuffers(
     video_encoder_->UseOutputBitstreamBuffer(media::BitstreamBuffer(
         i, output_buffers_[i]->handle(), output_buffers_[i]->mapped_size()));
   }
+  SignalAsyncWaiter(WEBRTC_VIDEO_CODEC_OK);

[Ami GONE FROM CHROMIUM, 2013/09/03 20:09:54]

Nothing guarantees that RequireBB will be called until Encode() is called, which
won't happen until initialization is done.  The justification for this in the CL
description is insufficient.
If RequireBB was really part of VEA initialization, then NotifyInitializeDone
should not be triggered before RBB/UOBB were done.  

[Pawel Osciak, 2013/09/04 01:34:47]

Well, if you look at how this class does it right now, it silently assumes that
RequireBB has been finished before first Encode() is called on RTCVE.
RTCVE::Encode() gets into Impl::Enqueue() and if input_buffers_free is empty, it
doesn't call EncodeOneFrame(), just returns, so Encode() will wait forever. My
CL is an attempt to fix this as well.

[Ami GONE FROM CHROMIUM, 2013/09/04 20:47:56]

sheu@'s point about input_coded_size is reasonable to me.  I forgot that we let
that bleed into the API but it certainly guarantees RBB before first Encode. 
The diff in this file is fine by me now.

 }
 
 void RTCVideoEncoder::Impl::BitstreamBufferReady(int32 bitstream_buffer_id,
@@ -614,10 +614,12 @@ void RTCVideoEncoder::ReturnEncodedImage(scoped_ptr<webrtc::EncodedImage> image,
     return;
 
   webrtc::CodecSpecificInfo info;
+  memset(&info, 0, sizeof(info));
   info.codecType = video_codec_type_;
 
   // Generate a header describing a single fragment.
   webrtc::RTPFragmentationHeader header;
+  memset(&header, 0, sizeof(header));
   header.VerifyAndAllocateFragmentationHeader(1);
   header.fragmentationOffset[0] = 0;
   header.fragmentationLength[0] = image->_length;