Do not wait for first video frame to start playing audio in a MediaStream.

content/renderer/media/webmediaplayer_ms.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/webmediaplayer_ms.h"
 
 #include <stddef.h>
 #include <limits>
 #include <string>
 #include <utility>
@@ skipping 134 matching lines @@
     SetNetworkState(WebMediaPlayer::NetworkStateNetworkError);
     return;
   }
 
   if (audio_renderer_) {
     audio_renderer_->SetVolume(volume_);
     audio_renderer_->Start();
   }
   if (video_frame_provider_)
     video_frame_provider_->Start();
-  if (audio_renderer_ && !video_frame_provider_) {
-    // This is audio-only mode.
+  if (audio_renderer_) {
+    // Do not wait for first video frame to start playing
     SetReadyState(WebMediaPlayer::ReadyStateHaveMetadata);
     SetReadyState(WebMediaPlayer::ReadyStateHaveEnoughData);
   }
 }
 
 void WebMediaPlayerMS::play() {
   DVLOG(1) << __FUNCTION__;
   DCHECK(thread_checker_.CalledOnValidThread());
 
   media_log_->AddEvent(media_log_->CreateEvent(media::MediaLogEvent::PLAY));
@@ skipping 314 matching lines @@
   if (frame->metadata()->GetTimeTicks(media::VideoFrameMetadata::REFERENCE_TIME,
                                       &render_time)) {
     TRACE_EVENT1("webrtc", "WebMediaPlayerMS::OnFrameAvailable",
                  "Ideal Render Instant", render_time.ToInternalValue());
   } else {
     TRACE_EVENT0("webrtc", "WebMediaPlayerMS::OnFrameAvailable");
   }
 
   if (!received_first_frame_) {
     received_first_frame_ = true;
-    SetReadyState(WebMediaPlayer::ReadyStateHaveMetadata);
-    SetReadyState(WebMediaPlayer::ReadyStateHaveEnoughData);
+    if (getReadyState() < WebMediaPlayer::ReadyStateHaveEnoughData) {
+      SetReadyState(WebMediaPlayer::ReadyStateHaveMetadata);
+      SetReadyState(WebMediaPlayer::ReadyStateHaveEnoughData);
+    }
 
     if (video_frame_provider_.get()) {
       video_weblayer_.reset(new cc_blink::WebLayerImpl(
           cc::VideoLayer::Create(compositor_.get(), media::VIDEO_ROTATION_0)));
       video_weblayer_->layer()->SetContentsOpaque(false);
       video_weblayer_->SetContentsOpaqueIsFixed(true);
       get_client()->setWebLayer(video_weblayer_.get());
     }
   }
 
@@ skipping 33 matching lines @@
 void WebMediaPlayerMS::ResetCanvasCache() {
   DCHECK(thread_checker_.CalledOnValidThread());
   video_renderer_.ResetCache();
 }
 
 void WebMediaPlayerMS::TriggerResize() {
   get_client()->sizeChanged();
 }
 
 }  // namespace content