Disable preroll duration increase on underflow for MediaSource playback.

webkit/renderer/media/webmediaplayer_impl.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 "webkit/renderer/media/webmediaplayer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 #include <vector>
@@ skipping 1032 matching lines @@
   else if (is_downloading && network_state_ == WebMediaPlayer::NetworkStateIdle)
     SetNetworkState(WebMediaPlayer::NetworkStateLoading);
   media_log_->AddEvent(
       media_log_->CreateBooleanEvent(
           media::MediaLogEvent::NETWORK_ACTIVITY_SET,
           "is_downloading_data", is_downloading));
 }
 
 void WebMediaPlayerImpl::StartPipeline(WebKit::WebMediaSource* media_source) {
   const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
-
+  bool increase_preroll_on_underflow = true;
 
   // Figure out which demuxer to use.
   if (!media_source) {
     DCHECK(!chunk_demuxer_);
     DCHECK(data_source_);
 
     demuxer_.reset(new media::FFmpegDemuxer(
         media_thread_.message_loop_proxy(), data_source_.get(),
         BIND_TO_RENDER_LOOP_2(&WebMediaPlayerImpl::OnNeedKey, "", "")));
   } else {
     DCHECK(!chunk_demuxer_);
     DCHECK(!data_source_);
 
     scoped_ptr<WebKit::WebMediaSource> ms(media_source);
     chunk_demuxer_ = new media::ChunkDemuxer(
         BIND_TO_RENDER_LOOP_1(&WebMediaPlayerImpl::OnDemuxerOpened,
                               base::Passed(&ms)),
         BIND_TO_RENDER_LOOP_2(&WebMediaPlayerImpl::OnNeedKey, "", ""),
         base::Bind(&WebMediaPlayerImpl::OnTextTrack, base::Unretained(this)),
         base::Bind(&LogMediaSourceError, media_log_));
     demuxer_.reset(chunk_demuxer_);
 
     // Disable GpuVideoDecoder creation until it supports codec config changes.
     // TODO(acolwell): Remove this once http://crbug.com/151045 is fixed.
     gpu_factories_ = NULL;
+
+    // Disable preroll increases on underflow since the web application has no
+    // way to detect that this is happening and runs the risk of triggering
+    // unwanted garbage collection if it is to aggressive about appending data.
+    // TODO(acolwell): Remove this once http://crbug.com/144683 is fixed.
+    increase_preroll_on_underflow = false;
   }
 
   scoped_ptr<media::FilterCollection> filter_collection(
       new media::FilterCollection());
   filter_collection->SetDemuxer(demuxer_.get());
 
   // Figure out if EME is enabled.
   media::SetDecryptorReadyCB set_decryptor_ready_cb;
   if (decryptor_) {
     set_decryptor_ready_cb = base::Bind(&ProxyDecryptor::SetDecryptorReadyCB,
                                         base::Unretained(decryptor_.get()));
   }
 
   // Create our audio decoders and renderer.
   ScopedVector<media::AudioDecoder> audio_decoders;
   audio_decoders.push_back(new media::FFmpegAudioDecoder(
       media_thread_.message_loop_proxy()));
   if (cmd_line->HasSwitch(switches::kEnableOpusPlayback)) {
     audio_decoders.push_back(new media::OpusAudioDecoder(
         media_thread_.message_loop_proxy()));
   }
 
   scoped_ptr<media::AudioRenderer> audio_renderer(
       new media::AudioRendererImpl(media_thread_.message_loop_proxy(),
                                    audio_source_provider_.get(),
                                    audio_decoders.Pass(),
-                                   set_decryptor_ready_cb));
+                                   set_decryptor_ready_cb,
+                                   increase_preroll_on_underflow));
   filter_collection->SetAudioRenderer(audio_renderer.Pass());
 
   // Create our video decoders and renderer.
   ScopedVector<media::VideoDecoder> video_decoders;
 
   if (gpu_factories_.get()) {
     video_decoders.push_back(new media::GpuVideoDecoder(
         media_thread_.message_loop_proxy(), gpu_factories_));
   }
 
@@ skipping 138 matching lines @@
 
   if (pending_repaint_)
     return;
 
   pending_repaint_ = true;
   main_loop_->PostTask(FROM_HERE, base::Bind(
       &WebMediaPlayerImpl::Repaint, AsWeakPtr()));
 }
 
 }  // namespace webkit_media