Adds power state suspend/resume messages to the webrtc native log.

content/browser/renderer_host/media/media_stream_manager.cc

Index: content/browser/renderer_host/media/media_stream_manager.cc
diff --git a/content/browser/renderer_host/media/media_stream_manager.cc b/content/browser/renderer_host/media/media_stream_manager.cc
index 839c0cb1411e529a53086eba615f945380d7ddc9..c6a4c25ce04e4b3d976c56623b26dd95e4b0dba0 100644
--- a/content/browser/renderer_host/media/media_stream_manager.cc
+++ b/content/browser/renderer_host/media/media_stream_manager.cc
@@ -11,6 +11,7 @@
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
+#include "base/power_monitor/power_monitor.h"
 #include "base/rand_util.h"
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
@@ -353,12 +354,24 @@ MediaStreamManager::MediaStreamManager(media::AudioManager* audio_manager)
         base::Bind(&MediaStreamManager::InitializeDeviceManagersOnIOThread,
                    base::Unretained(this)));
   }
+
+  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
+  // BrowserMainLoop always creates the PowerMonitor instance before creating
+  // MediaStreamManager, but power_monitor may be NULL in unit tests.
+  if (power_monitor)
+    power_monitor->AddObserver(this);
 }
 
 MediaStreamManager::~MediaStreamManager() {
   DVLOG(1) << "~MediaStreamManager";
   DCHECK(requests_.empty());
   DCHECK(!device_task_runner_);
+
+  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
+  // The PowerMonitor instance owned by BrowserMainLoops always outlives the
+  // MediaStreamManager, but it may be NULL in unit tests.
+  if (power_monitor)
+    power_monitor->RemoveObserver(this);
 }
 
 VideoCaptureManager* MediaStreamManager::video_capture_manager() {
@@ -1581,6 +1594,14 @@ void MediaStreamManager::SendMessageToNativeLog(const std::string& message) {
       base::Bind(DoAddLogMessage, message));
 }
 
+void MediaStreamManager::OnSuspend() {
+  SendMessageToNativeLog("Power state suspended.");
+}
+
+void MediaStreamManager::OnResume() {
+  SendMessageToNativeLog("Power state resumed.");
+}
+
 void MediaStreamManager::AddLogMessageOnIOThread(const std::string& message) {
   // Get render process ids on the IO thread.
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));