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

content/browser/media/audio_stream_monitor.cc

Index: content/browser/media/audio_stream_monitor.cc
diff --git a/content/browser/media/audio_stream_monitor.cc b/content/browser/media/audio_stream_monitor.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1d2f76f7f2c02f986f5b52122834363ff96be1e8
--- /dev/null
+++ b/content/browser/media/audio_stream_monitor.cc
@@ -0,0 +1,162 @@
+// 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 "content/browser/media/audio_stream_monitor.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/invalidate_type.h"
+#include "content/public/browser/render_frame_host.h"
+
+namespace content {
+
+namespace {
+
+AudioStreamMonitor* AudioStreamMonitorFromRenderFrame(int render_process_id,
+                                                      int render_frame_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  WebContentsImpl* const web_contents =
+      static_cast<WebContentsImpl*>(WebContents::FromRenderFrameHost(
+          RenderFrameHost::FromID(render_process_id, render_frame_id)));
+  return web_contents ? web_contents->audio_stream_monitor() : NULL;
+}
+
+}  // namespace
+
+AudioStreamMonitor::AudioStreamMonitor(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_;
+}
+
+// static
+void AudioStreamMonitor::StartMonitoringStream(
+    int render_process_id,
+    int render_frame_id,
+    int stream_id,
+    const ReadPowerAndClipCallback& read_power_callback) {
+  if (!monitoring_available())
+    return;
+  BrowserThread::PostTask(BrowserThread::UI,
+                          FROM_HERE,
+                          base::Bind(&StartMonitoringHelper,
+                                     render_process_id,
+                                     render_frame_id,
+                                     stream_id,
+                                     read_power_callback));
+}
+
+// static
+void AudioStreamMonitor::StopMonitoringStream(int render_process_id,
+                                              int render_frame_id,
+                                              int stream_id) {
+  if (!monitoring_available())
+    return;
+  BrowserThread::PostTask(BrowserThread::UI,
+                          FROM_HERE,
+                          base::Bind(&StopMonitoringHelper,
+                                     render_process_id,
+                                     render_frame_id,
+                                     stream_id));
+}
+
+// static
+void AudioStreamMonitor::StartMonitoringHelper(
+    int render_process_id,
+    int render_frame_id,
+    int stream_id,
+    const ReadPowerAndClipCallback& read_power_callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  AudioStreamMonitor* const monitor =
+      AudioStreamMonitorFromRenderFrame(render_process_id, render_frame_id);
+  if (monitor) {
+    monitor->StartMonitoringStreamOnUIThread(
+        render_process_id, stream_id, read_power_callback);
+  }
+}
+
+// static
+void AudioStreamMonitor::StopMonitoringHelper(int render_process_id,
+                                              int render_frame_id,
+                                              int stream_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  AudioStreamMonitor* const monitor =
+      AudioStreamMonitorFromRenderFrame(render_process_id, render_frame_id);
+  if (monitor)
+    monitor->StopMonitoringStreamOnUIThread(render_process_id, stream_id);
+}
+
+void AudioStreamMonitor::StartMonitoringStreamOnUIThread(
+    int render_process_id,
+    int stream_id,
+    const ReadPowerAndClipCallback& read_power_callback) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!read_power_callback.is_null());
+  poll_callbacks_[StreamID(render_process_id, 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::StopMonitoringStreamOnUIThread(int render_process_id,
+                                                        int stream_id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  poll_callbacks_.erase(StreamID(render_process_id, 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(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)));
+  }
+}
+
+}  // namespace content