Add histograms for MediaRecorder

This CL adds 2 new MediaRecorder histograms, one for the errors
HW encode encounters and one for whether HW encode is used.

ChromeOS autotest (crrev.com/c/813974 and crrev.com/c/831318) will
use them to determine if tests pass.

BUG=616659
TEST=Verified with autotests that the histograms appear.

Change-Id: Id7533e1df7d2105490085eadda061a117b466d59
Reviewed-on: https://chromium-review.googlesource.com/831773
Commit-Queue: Sheng-hao Tsao <shenghao@google.com>
Reviewed-by: Gayane Petrosyan <gayane@chromium.org>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525992}

content/renderer/media_recorder/vea_encoder.cc

@@ -7,6 +7,7 @@
 #include <string>
 
 #include "base/containers/queue.h"
+#include "base/metrics/histogram_macros.h"
 #include "content/renderer/media/gpu/gpu_video_accelerator_factories_impl.h"
 #include "content/renderer/render_thread_impl.h"
 #include "media/base/bind_to_current_loop.h"
@@ -119,6 +120,8 @@ void VEAEncoder::BitstreamBufferReady(int32_t bitstream_buffer_id,
 void VEAEncoder::NotifyError(media::VideoEncodeAccelerator::Error error) {
   DVLOG(3) << __func__;
   DCHECK(encoding_task_runner_->BelongsToCurrentThread());
+  UMA_HISTOGRAM_ENUMERATION("Media.MediaRecorder.VEAError", error,
+                            media::VideoEncodeAccelerator::kErrorMax + 1);
   on_error_callback_.Run();
   error_notified_ = true;
 }

content/renderer/media_recorder/video_track_recorder.cc

@@ -10,6 +10,7 @@
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/task_runner_util.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ -455,6 +456,7 @@ void VideoTrackRecorder::InitializeEncoder(
   const gfx::Size& input_size = frame->visible_rect().size();
   if (allow_vea_encoder && CanUseAcceleratedEncoder(codec, input_size.width(),
                                                     input_size.height())) {
+    UMA_HISTOGRAM_BOOLEAN("Media.MediaRecorder.VEAUsed", true);
     const auto vea_profile = GetCodecEnumerator()->CodecIdToVEAProfile(codec);
     encoder_ = new VEAEncoder(
         on_encoded_video_callback,
@@ -462,6 +464,7 @@ void VideoTrackRecorder::InitializeEncoder(
                                             weak_ptr_factory_.GetWeakPtr())),
         bits_per_second, vea_profile, input_size);
   } else {
+    UMA_HISTOGRAM_BOOLEAN("Media.MediaRecorder.VEAUsed", false);
     switch (codec) {
 #if BUILDFLAG(RTC_USE_H264)
       case CodecId::H264:

tools/metrics/histograms/enums.xml

@@ -27568,6 +27568,11 @@ Called by update_use_counter_css.py.-->
   <int value="1" label="Has errors"/>
 </enum>
 
+<enum name="MediaRecorderVEAUsed">
+  <int value="0" label="Not used"/>
+  <int value="1" label="Used"/>
+</enum>
+
 <enum name="MediaRouteProviderResult">
   <int value="0" label="UnknownError"/>
   <int value="1" label="Ok"/>

tools/metrics/histograms/histograms.xml

@@ -34520,6 +34520,19 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Media.MediaRecorder.VEAError"
+    enum="VideoDecodeAcceleratorError">
+  <owner>shenghao@chromium.org</owner>
+  <owner>mcasas@chromium.org</owner>
+  <summary>The errors HW video encode encounters in MediaRecorder.</summary>
+</histogram>
+
+<histogram name="Media.MediaRecorder.VEAUsed" enum="MediaRecorderVEAUsed">
+  <owner>shenghao@chromium.org</owner>
+  <owner>mcasas@chromium.org</owner>
+  <summary>Whether HW video encode is used in MediaRecorder.</summary>
+</histogram>
+
 <histogram name="Media.MicrophoneMuted" enum="MicrophoneMuteResult">
   <owner>henrika@chromium.org</owner>
   <summary>