Add methods for telling V8 how much memory audio/video is using.

media/base/pipeline.cc

Index: media/base/pipeline.cc
diff --git a/media/base/pipeline.cc b/media/base/pipeline.cc
index 387470aec070dd242e5486419f9efb15d859a2fa..90a090b4fccf140ff8753a4dbd9eb9bc8d78143d 100644
--- a/media/base/pipeline.cc
+++ b/media/base/pipeline.cc
@@ -46,6 +46,11 @@ Pipeline::Pipeline(
       pending_cdm_context_(nullptr),
       weak_factory_(this) {
   media_log_->AddEvent(media_log_->CreatePipelineStateChangedEvent(kCreated));
+
+  // By default these values are initialized to -1 to indicate no data, but
+  // Pipeline clients should always see a zero value in these cases.
+  statistics_.audio_memory_usage = 0;
+  statistics_.video_memory_usage = 0;
 }
 
 Pipeline::~Pipeline() {
@@ -472,6 +477,11 @@ void Pipeline::OnUpdateStatistics(const PipelineStatistics& stats) {
   statistics_.video_bytes_decoded += stats.video_bytes_decoded;
   statistics_.video_frames_decoded += stats.video_frames_decoded;
   statistics_.video_frames_dropped += stats.video_frames_dropped;
+
+  if (stats.audio_memory_usage >= 0)
+    statistics_.audio_memory_usage = stats.audio_memory_usage;
+  if (stats.video_memory_usage >= 0)
+    statistics_.video_memory_usage = stats.video_memory_usage;
 }
 
 void Pipeline::StartTask() {