Add support for single sample metrics.

content/renderer/media/render_media_log.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/render_media_log.h"
 
 #include <sstream>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/metrics/single_value_histograms.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/default_tick_clock.h"
 #include "content/common/view_messages.h"
 #include "content/public/common/content_client.h"
+#include "content/public/common/service_names.mojom.h"
 #include "content/public/renderer/content_renderer_client.h"
 #include "content/public/renderer/render_thread.h"
 
 #ifndef MEDIA_EVENT_LOG_UTILITY
 #define MEDIA_EVENT_LOG_UTILITY DVLOG(1)
 #endif
 
 namespace {
 
 // Print an event to the chromium log.
@@ skipping 17 matching lines @@
 
 RenderMediaLog::RenderMediaLog(const GURL& security_origin)
     : security_origin_(security_origin),
       task_runner_(base::ThreadTaskRunnerHandle::Get()),
       tick_clock_(new base::DefaultTickClock()),
       last_ipc_send_time_(tick_clock_->NowTicks()),
       ipc_send_pending_(false),
       weak_factory_(this) {
   DCHECK(RenderThread::Get())
       << "RenderMediaLog must be constructed on the render thread";
+
+  std::unique_ptr<base::SingleValueCountsHistogram> metric_1(
+      base::SingleValueHistogramsFactory::Get()
+          ->CreateSingleValueCountsHistogram(
+              "Media.VideoRenderer.CadenceChanges", 1, 10, 10));
+  metric_1->SetSample(3);
+  metric_1->SetSample(2);
+
+  std::unique_ptr<base::SingleValueCountsHistogram> metric_2(
+      base::SingleValueHistogramsFactory::Get()
+          ->CreateSingleValueCountsHistogram(
+              "Media.VideoRenderer.CadenceChanges", 1, 10, 10));
+  metric_2->SetSample(5);
+  metric_2->SetSample(8);
+
   // Pre-bind the WeakPtr on the right thread since we'll receive calls from
   // other threads and don't want races.
   weak_this_ = weak_factory_.GetWeakPtr();
 }
 
 RenderMediaLog::~RenderMediaLog() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   // There's no further chance to handle this, so send them now. This should not
   // be racy since nothing should have a pointer to the media log on another
@@ skipping 140 matching lines @@
   tick_clock_.swap(tick_clock);
   last_ipc_send_time_ = tick_clock_->NowTicks();
 }
 
 void RenderMediaLog::SetTaskRunnerForTesting(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) {
   task_runner_ = task_runner;
 }
 
 }  // namespace content