Experiment with more aggressive MSE GC on memory pressure

media/blink/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 "media/blink/webmediaplayer_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/alias.h"
 #include "base/debug/crash_logging.h"
 #include "base/location.h"
+#include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/task_runner_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "cc/blink/web_layer_impl.h"
 #include "cc/layers/video_layer.h"
 #include "media/audio/null_audio_sink.h"
@@ skipping 1130 matching lines @@
 
   UpdateBackgroundVideoOptimizationState();
 }
 
 void WebMediaPlayerImpl::OnDemuxerOpened() {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
   client_->mediaSourceOpened(
       new WebMediaSourceImpl(chunk_demuxer_, media_log_));
 }
 
+void WebMediaPlayerImpl::OnMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  DVLOG(2) << __func__ << " memory_pressure_level=" << memory_pressure_level;
+  DCHECK(main_task_runner_->BelongsToCurrentThread());
+  DCHECK(base::FeatureList::IsEnabled(kReduceMSEBuffersOnMemoryPressure));

[DaleCurtis, 2017/01/26 19:24:50]

Seems this should include both features?

[servolk, 2017/01/26 19:38:31]

No, the kMSEInstantGCOnMemoryPressure may or may not be enabled here. If
kMSEInstantGCOnMemoryPressure is enabled, then we'll perform GC immediately
within this call. If kMSEInstantGCOnMemoryPressure is disabled, then we'll just
remember the memory pressure state in the SourceBufferStream and that'll take
effect on the next append operation.

+  if (chunk_demuxer_) {
+    // base::Unretained is safe, since chunk_demuxer_ is actually owned by
+    // |this| via this->demuxer_.
+    media_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&ChunkDemuxer::OnMemoryPressure,
+                              base::Unretained(chunk_demuxer_),
+                              base::TimeDelta::FromSecondsD(currentTime()),
+                              memory_pressure_level));
+  }
+}
+
 void WebMediaPlayerImpl::OnError(PipelineStatus status) {
   DVLOG(1) << __func__;
   DCHECK(main_task_runner_->BelongsToCurrentThread());
   DCHECK_NE(status, PIPELINE_OK);
 
   if (suppress_destruction_errors_)
     return;
 
   ReportPipelineError(load_type_, frame_->getSecurityOrigin(), status);
   media_log_->AddEvent(media_log_->CreatePipelineErrorEvent(status));
@@ skipping 529 matching lines @@
     return;
 #endif
   } else {
     DCHECK(!chunk_demuxer_);
     DCHECK(!data_source_);
 
     chunk_demuxer_ = new ChunkDemuxer(
         BIND_TO_RENDER_LOOP(&WebMediaPlayerImpl::OnDemuxerOpened),
         encrypted_media_init_data_cb, media_log_);
     demuxer_.reset(chunk_demuxer_);
+
+    if (base::FeatureList::IsEnabled(kReduceMSEBuffersOnMemoryPressure)) {
+      // base::Unretained is safe because |this| owns memory_pressure_listener_.
+      memory_pressure_listener_ =
+          base::MakeUnique<base::MemoryPressureListener>(base::Bind(
+              &WebMediaPlayerImpl::OnMemoryPressure, base::Unretained(this)));
+    }
   }
 
   // TODO(sandersd): FileSystem objects may also be non-static, but due to our
   // caching layer such situations are broken already. http://crbug.com/593159
   bool is_static = !chunk_demuxer_;
   bool is_streaming = IsStreaming();
   UMA_HISTOGRAM_BOOLEAN("Media.IsStreaming", is_streaming);
 
   // ... and we're ready to go!
   // TODO(sandersd): On Android, defer Start() if the tab is not visible.
@@ skipping 527 matching lines @@
     UMA_HISTOGRAM_TIMES(
         "Media.Video.TimeFromForegroundToFirstFrame.DisableTrack",
         time_to_first_frame);
   } else {
     UMA_HISTOGRAM_TIMES("Media.Video.TimeFromForegroundToFirstFrame.Paused",
                         time_to_first_frame);
   }
 }
 
 }  // namespace media