[scheduler] Plumb information about active webrtc connections to scheduler

third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.cpp

Index: third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.cpp
diff --git a/third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.cpp b/third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.cpp
index 85cb675df52591ff30a073a66e2606b8d9868286..df9d88ec758b195311ddb78892e82de4f0d8d9d7 100644
--- a/third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.cpp
+++ b/third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.cpp
@@ -521,6 +521,9 @@ RTCPeerConnection::RTCPeerConnection(ExecutionContext* context,
         NotSupportedError, "Failed to initialize native PeerConnection.");
     return;
   }
+
+  m_connectionHandleForScheduler =
+      document->frame()->frameScheduler()->onActiveConnectionCreated();

[haraken, 2017/02/10 16:51:20]

Another possible API would be to use an observer pattern like
ActiveScriptWrappable::hasPendingActivity().

class RTCPeerConnection : public HasUnthrottledTask {
  bool hasUnthrottledTask() override { return !m_closed || !m_stopped; }
};

Then developers don't need to write .reset() in many places. The observer
pattern would be less error-prone than the .reset() pattern.

[altimin, 2017/02/10 16:57:00]

I would argue that you still need to notify the scheduler when active connection
has gone away (checking all HasActiveTask subclasses is slow and will probably
involve troubles with ownership models and weak pointers). Thus some kind of
call is needed, and resetting handlers is arguably one of the best options: e.g.
calling reset on an empty handle or calling reset twice will work as intended.

 }
 
 RTCPeerConnection::~RTCPeerConnection() {
@@ -1352,6 +1355,8 @@ void RTCPeerConnection::releasePeerConnectionHandler() {
   m_dispatchScheduledEventRunner->stop();
 
   m_peerHandler.reset();
+
+  m_connectionHandleForScheduler.reset();
 }
 
 void RTCPeerConnection::closePeerConnection() {
@@ -1426,6 +1431,8 @@ void RTCPeerConnection::closeInternal() {
   Document* document = toDocument(getExecutionContext());
   HostsUsingFeatures::countAnyWorld(
       *document, HostsUsingFeatures::Feature::RTCPeerConnectionUsed);
+
+  m_connectionHandleForScheduler.reset();
 }
 
 void RTCPeerConnection::scheduleDispatchEvent(Event* event) {