Audio output controller lifetime UMA

To understand why we get count mismatches for AudioOutputController
stats when running the audio service in- and out-of-process.

Bug: 867827
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I5d1dbe62ff07d91d48ff67a49b86a14cd071623d
Reviewed-on: https://chromium-review.googlesource.com/1250962Reviewed-by: Max Morin <maxmorin@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Olga Sharonova <olka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595399}

media/audio/audio_output_controller.cc

@@ -96,6 +96,7 @@ AudioOutputController::AudioOutputController(
       params_(params),
       handler_(handler),
       task_runner_(audio_manager->GetTaskRunner()),
+      construction_time_(base::TimeTicks::Now()),
       output_device_id_(output_device_id),
       stream_(NULL),
       diverting_to_stream_(NULL),
@@ -118,6 +119,8 @@ AudioOutputController::~AudioOutputController() {
   CHECK_EQ(kClosed, state_);
   CHECK_EQ(nullptr, stream_);
   CHECK(duplication_targets_.empty());
+  UMA_HISTOGRAM_LONG_TIMES("Media.AudioOutputController.LifeTime",
+                           base::TimeTicks::Now() - construction_time_);
 }
 
 // static

media/audio/audio_output_controller.h

@@ -276,6 +276,10 @@ class MEDIA_EXPORT AudioOutputController
   // The message loop of audio manager thread that this object runs on.
   const scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
+  // Time when the controller is constructed. Used to record its lifetime on
+  // destruction.
+  const base::TimeTicks construction_time_;
+
   // Specifies the device id of the output device to open or empty for the
   // default output device.
   std::string output_device_id_;

services/audio/output_controller.cc

@@ -127,6 +127,7 @@ OutputController::OutputController(
       params_(params),
       handler_(handler),
       task_runner_(audio_manager->GetTaskRunner()),
+      construction_time_(base::TimeTicks::Now()),
       output_device_id_(output_device_id),
       stream_(NULL),
       disable_local_output_(false),
@@ -153,6 +154,8 @@ OutputController::~OutputController() {
   DCHECK_EQ(nullptr, stream_);
   DCHECK(snoopers_.empty());
   DCHECK(should_duplicate_.IsZero());
+  UMA_HISTOGRAM_LONG_TIMES("Media.AudioOutputController.LifeTime",
+                           base::TimeTicks::Now() - construction_time_);
 }
 
 bool OutputController::Create(bool is_for_device_change) {

services/audio/output_controller.h

@@ -242,6 +242,10 @@ class OutputController : public media::AudioOutputStream::AudioSourceCallback,
   // via tasks run by this TaskRunner.
   const scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
+  // Time when the controller is constructed. Used to record its lifetime on
+  // destruction.
+  const base::TimeTicks construction_time_;
+
   // Specifies the device id of the output device to open or empty for the
   // default output device.
   const std::string output_device_id_;

tools/metrics/histograms/histograms.xml

@@ -42016,6 +42016,17 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="Media.AudioOutputController.LifeTime" units="ms"
+    expires_after="2019-02-01">
+  <owner>olka@chromium.org</owner>
+  <owner>marinaciocea@chromium.org</owner>
+  <owner>maxmorin@chromium.org</owner>
+  <summary>
+    Time interval from the output stream controller construction to its
+    destruction.
+  </summary>
+</histogram>
+
 <histogram name="Media.AudioOutputController.ProxyStreamCreationResult"
     enum="AudioOutputStreamCreationResult">
   <owner>maxmorin@chromium.org</owner>