Exposing memory metrics for WebMediaPlayer via metrics emitter

Previous CL removed hand made memory related UMAs for WMP.
This CL uses the standard way to expose similar memory metrics.

The only interesting part is where we change memory dump naming
format from:
  media/webmediaplayer/player_%d/{video|audio}
to
  media/webmediaplayer/{video|audio}/player_%d

This is done in order to have readily available aggregating top
level nodes where total video or audio memory consumption can
be found.

Bug: 1056839
Change-Id: Ibf8d57da47f54b90ff4e3fe207d351ee043aa41c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2109461
Commit-Queue: Eugene Zemtsov <eugene@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Takashi Sakamoto <tasak@google.com>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751923}

chrome/browser/metrics/process_memory_metrics_emitter.cc

@@ -179,6 +179,14 @@ const Metric kAllocatorDumpNamesForMetrics[] = {
     {"mojo", "NumberOfMojoHandles", MetricSize::kSmall,
      MemoryAllocatorDump::kNameObjectCount, EmitTo::kCountsInUkmOnly,
      &Memory_Experimental::SetNumberOfMojoHandles},
+    {"media/webmediaplayer/audio", "WebMediaPlayer.Audio", MetricSize::kSmall,
+     kSize, EmitTo::kSizeInUmaOnly, nullptr},
+    {"media/webmediaplayer/video", "WebMediaPlayer.Video", MetricSize::kLarge,
+     kSize, EmitTo::kSizeInUmaOnly, nullptr},
+    {"media/webmediaplayer/data_source", "WebMediaPlayer.DataSource",
+     MetricSize::kLarge, kSize, EmitTo::kSizeInUmaOnly, nullptr},
+    {"media/webmediaplayer/demuxer", "WebMediaPlayer.Demuxer",
+     MetricSize::kLarge, kSize, EmitTo::kSizeInUmaOnly, nullptr},
     {"net", "Net", MetricSize::kSmall, kEffectiveSize, EmitTo::kSizeInUkmAndUma,
      &Memory_Experimental::SetNet},
     {"net/url_request_context", "Net.UrlRequestContext", MetricSize::kSmall,

media/blink/webmediaplayer_impl.cc

@@ -272,7 +272,7 @@ void CreateAllocation(base::trace_event::ProcessMemoryDump* pmd,
   if (bytes <= 0)
     return;
   auto full_name =
-      base::StringPrintf("media/webmediaplayer/player_%d/%s", id, name);
+      base::StringPrintf("media/webmediaplayer/%s/player_%d", name, id);
   auto* dump = pmd->CreateAllocatorDump(full_name);
 
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
@@ -3220,13 +3220,13 @@ void WebMediaPlayerImpl::OnMainThreadMemoryDump(
   const PipelineStatistics stats = GetPipelineStatistics();
 
   bool suspended = pipeline_controller_->IsPipelineSuspended();
-  auto parent_dump_name =
+  auto state_node_name =
       base::StringPrintf("media/webmediaplayer/player_%d", id);
   auto player_state =
       base::StringPrintf("Paused: %d Ended: %d ReadyState: %d Suspended: %d",
                          paused_, ended_, GetReadyState(), suspended);
-  auto* parent_dump = pmd->CreateAllocatorDump(parent_dump_name);
-  parent_dump->AddString("player_state", "", player_state);
+  auto* state_node = pmd->CreateAllocatorDump(state_node_name);
+  state_node->AddString("player_state", "", player_state);
 
   CreateAllocation(pmd, id, "audio", stats.audio_memory_usage);
   CreateAllocation(pmd, id, "video", stats.video_memory_usage);

media/blink/webmediaplayer_impl_unittest.cc

@@ -2092,7 +2092,7 @@ TEST_F(WebMediaPlayerImplTest, MemDumpReporting) {
 
         for (const char* name : allocations) {
           auto it = dumps.find(base::StringPrintf(
-              "media/webmediaplayer/player_%d/%s", ctx->id, name));
+              "media/webmediaplayer/%s/player_%d", name, ctx->id));
           ASSERT_NE(dumps.end(), it) << name;
           ASSERT_GT(it->second->GetSizeInternal(), 0u) << name;
         }