Android: move peerconnection out of power observer.

Currently when screen is off (or Chrome goes to background) for more than 1 min,
peerconnection will be stoppted by PowerMonitor to save battery power. This is
not necesary now since we'll suspend video call when the tab is background. And
users prefer that audio call can continue while they are doing something else.

BUG=513633

Review-Url: https://codereview.chromium.org/2263373003
Cr-Commit-Position: refs/heads/master@{#415372}

content/renderer/media/peer_connection_tracker.cc

@@ -376,10 +376,15 @@ RenderThread* PeerConnectionTracker::SendTarget() {
 
 void PeerConnectionTracker::OnSuspend() {
   DCHECK(main_thread_.CalledOnValidThread());
+// On Android 'Suspend' means more of the activity state. So it's better to
+// keep the webrtc call session when user is doing something else or screen
+// is off.
+#if !defined(OS_ANDROID)
   for (PeerConnectionIdMap::iterator it = peer_connection_id_map_.begin();
        it != peer_connection_id_map_.end(); ++it) {
     it->first->CloseClientPeerConnection();
   }
+#endif
 }
 
 void PeerConnectionTracker::OnStartEventLog(int peer_connection_id,

content/renderer/media/peer_connection_tracker_unittest.cc

@@ -44,6 +44,7 @@ bool MockSendTargetThread::OnMessageReceived(const IPC::Message& msg) {
 class MockPeerConnectionHandler : public RTCPeerConnectionHandler {
  public:
   MockPeerConnectionHandler() : RTCPeerConnectionHandler(&client_, nullptr) {}
+  MOCK_METHOD0(CloseClientPeerConnection, void());
 
  private:
   MockWebRTCPeerConnectionHandlerClient client_;
@@ -77,6 +78,26 @@ TEST(PeerConnectionTrackerTest, TrackCreateOffer) {
   tracker.TrackCreateOffer(&pc_handler, options);
 }
 
+TEST(PeerConnectionTrackerTest, OnSuspend) {
+  PeerConnectionTracker tracker;
+  // Initialization stuff.
+  MockPeerConnectionHandler pc_handler;
+  MockSendTargetThread target_thread;
+  webrtc::PeerConnectionInterface::RTCConfiguration config;
+  blink::WebMediaConstraints constraints;
+  tracker.OverrideSendTargetForTesting(&target_thread);
+  EXPECT_CALL(target_thread, OnAddPeerConnection(_));
+  tracker.RegisterPeerConnection(&pc_handler, config, constraints, nullptr);
+// Back to the test.
+#if defined(OS_ANDROID)
+  EXPECT_CALL(pc_handler, CloseClientPeerConnection()).Times(0);
+#else
+  EXPECT_CALL(pc_handler, CloseClientPeerConnection());
+#endif
+  std::unique_ptr<IPC::Message> message(new PeerConnectionTracker_OnSuspend());
+  tracker.OnControlMessageReceived(*message.get());
+}
+
 // TODO(hta): Write tests for the other tracking functions.
 
 }  // namespace

content/renderer/media/rtc_peer_connection_handler.h

@@ -165,7 +165,8 @@ class CONTENT_EXPORT RTCPeerConnectionHandler
                 blink::WebMediaStreamSource::Type track_type);
 
   // Tells the |client_| to close RTCPeerConnection.
-  void CloseClientPeerConnection();
+  // Make it virtual for testing purpose.
+  virtual void CloseClientPeerConnection();
 
   // Start recording an event log.
   void StartEventLog(IPC::PlatformFileForTransit file,