Report WMPI components memory usage to UMA

media/blink/webmediaplayer_impl.h

Index: media/blink/webmediaplayer_impl.h
diff --git a/media/blink/webmediaplayer_impl.h b/media/blink/webmediaplayer_impl.h
index 6e01840d71c6e0e05129c139d91354fd04f2f4d9..078f79e94683b3cab4833d7091f69e4a756c826b 100644
--- a/media/blink/webmediaplayer_impl.h
+++ b/media/blink/webmediaplayer_impl.h
@@ -15,8 +15,10 @@
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/linked_ptr.h"
+#include "base/memory/memory_pressure_listener.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.h"
 #include "base/threading/thread.h"
 #include "base/time/default_tick_clock.h"
 #include "base/timer/elapsed_timer.h"
@@ -345,9 +347,14 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   // Called at low frequency to tell external observers how much memory we're
   // using for video playback.  Called by |memory_usage_reporting_timer_|.
   // Memory usage reporting is done in two steps, because |demuxer_| must be
-  // accessed on the media thread.
-  void ReportMemoryUsage();
-  void FinishMemoryUsageReport(int64_t demuxer_memory_usage);
+  // accessed on the media thread. Also called when we get notified about memory

[watk, 2016/12/13 23:34:31]

nit: merge the "Also called when" sentence with the "Called by" above.

[servolk, 2016/12/14 00:07:23]

Done.

+  // pressure level changes.
+  void ReportMemoryUsageOnTimer();
+  using MaybeMemPressureLvl =

[watk, 2016/12/13 23:34:31]

nit: It's probably more obvious if you call this OptionalMemoryPressureLevel

[servolk, 2016/12/14 00:07:23]

Done.

+      base::Optional<base::MemoryPressureListener::MemoryPressureLevel>;
+  void ReportMemoryUsage(MaybeMemPressureLvl maybe_mem_pressure_lvl);
+  void FinishMemoryUsageReport(MaybeMemPressureLvl maybe_mem_pressure_lvl,
+                               int64_t demuxer_memory_usage);

[watk, 2016/12/13 23:34:31]

nit: This is minor but I'd s/lvl/level and s/mem/memory everywhere. Both lvl and
mem are well known enough that I think they're within the style guide
recommendation for abbreviations, but they're uncommon in media code at least.
(e.g.,
https://cs.chromium.org/search/?q=file:media/+lvl%5Cb&sq=package:chromium&typ...)

Up to you though.

[servolk, 2016/12/14 00:07:23]

Done.

 
   // Called during OnHidden() when we want a suspended player to enter the
   // paused state after some idle timeout.
@@ -358,6 +365,8 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   // Returns true if the player is hidden.
   bool IsHidden() const;
 
+  void OnMemoryPressure(base::MemoryPressureListener::MemoryPressureLevel lvl);
+
   blink::WebLocalFrame* frame_;
 
   // The playback state last reported to |delegate_|, to avoid setting duplicate
@@ -579,6 +588,8 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   // Whether the player is currently in autoplay muted state.
   bool autoplay_muted_ = false;
 
+  std::unique_ptr<base::MemoryPressureListener> mem_pressure_listener_;
+
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerImpl);
 };