Revert of Gardening: Revert "Use AudioStreamMonitor to control power save blocking."

chrome/browser/media/audio_stream_monitor.cc

-// Copyright 2014 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 "chrome/browser/media/audio_stream_monitor.h"
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "content/public/browser/invalidate_type.h"
-#include "content/public/browser/web_contents.h"
-
-DEFINE_WEB_CONTENTS_USER_DATA_KEY(AudioStreamMonitor);
-
-AudioStreamMonitor::AudioStreamMonitor(content::WebContents* contents)
-    : web_contents_(contents),
-      clock_(&default_tick_clock_),
-      was_recently_audible_(false) {
-  DCHECK(web_contents_);
-}
-
-AudioStreamMonitor::~AudioStreamMonitor() {}
-
-bool AudioStreamMonitor::WasRecentlyAudible() const {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  return was_recently_audible_;
-}
-
-void AudioStreamMonitor::StartMonitoringStream(
-    int stream_id,
-    const ReadPowerAndClipCallback& read_power_callback) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(!read_power_callback.is_null());
-  poll_callbacks_[stream_id] = read_power_callback;
-  if (!poll_timer_.IsRunning()) {
-    poll_timer_.Start(
-        FROM_HERE,
-        base::TimeDelta::FromSeconds(1) / kPowerMeasurementsPerSecond,
-        base::Bind(&AudioStreamMonitor::Poll, base::Unretained(this)));
-  }
-}
-
-void AudioStreamMonitor::StopMonitoringStream(int stream_id) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  poll_callbacks_.erase(stream_id);
-  if (poll_callbacks_.empty())
-    poll_timer_.Stop();
-}
-
-void AudioStreamMonitor::Poll() {
-  for (StreamPollCallbackMap::const_iterator it = poll_callbacks_.begin();
-       it != poll_callbacks_.end();
-       ++it) {
-    // TODO(miu): A new UI for delivering specific power level and clipping
-    // information is still in the works.  For now, we throw away all
-    // information except for "is it audible?"
-    const float power_dbfs = it->second.Run().first;
-    const float kSilenceThresholdDBFS = -72.24719896f;
-    if (power_dbfs >= kSilenceThresholdDBFS) {
-      last_blurt_time_ = clock_->NowTicks();
-      MaybeToggle();
-      break;  // No need to poll remaining streams.
-    }
-  }
-}
-
-void AudioStreamMonitor::MaybeToggle() {
-  const bool indicator_was_on = was_recently_audible_;
-  const base::TimeTicks off_time =
-      last_blurt_time_ + base::TimeDelta::FromMilliseconds(kHoldOnMilliseconds);
-  const base::TimeTicks now = clock_->NowTicks();
-  const bool should_indicator_be_on = now < off_time;
-
-  if (should_indicator_be_on != indicator_was_on) {
-    was_recently_audible_ = should_indicator_be_on;
-    web_contents_->NotifyNavigationStateChanged(content::INVALIDATE_TYPE_TAB);
-  }
-
-  if (!should_indicator_be_on) {
-    off_timer_.Stop();
-  } else if (!off_timer_.IsRunning()) {
-    off_timer_.Start(
-        FROM_HERE,
-        off_time - now,
-        base::Bind(&AudioStreamMonitor::MaybeToggle, base::Unretained(this)));
-  }
-}