Preparation for new Promise-based RTCPeerConnection.getStats.

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

Index: third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.idl
diff --git a/third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.idl b/third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.idl
index 1afa9291abfb67d05ebca101393fbcccedb1385e..e61d1914d0491d29e9c0609ae2372549e4037383 100644
--- a/third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.idl
+++ b/third_party/WebKit/Source/modules/peerconnection/RTCPeerConnection.idl
@@ -104,10 +104,20 @@ enum RTCIceConnectionState {
     // TODO(guidou): The failureCallback argument should be non-optional.
     [CallWith=ScriptState] Promise<void> setRemoteDescription(RTCSessionDescriptionInit description, VoidCallback successCallback, [Default=Undefined] optional RTCPeerConnectionErrorCallback failureCallback);
     [CallWith=ScriptState, MeasureAs=RTCPeerConnectionAddIceCandidateLegacy] Promise<void> addIceCandidate((RTCIceCandidateInit or RTCIceCandidate) candidate, VoidCallback successCallback, RTCPeerConnectionErrorCallback failureCallback);
+
     // TODO(guidou): The selector argument should the first (nullable,
     // non-optional) argument, and there should be a third failureCallback
     // argument.
-    [CallWith=ExecutionContext, LegacyInterfaceTypeChecking] void getStats(RTCStatsCallback successCallback, [Default=Undefined] optional MediaStreamTrack selector);
+    // TODO(hbos): This is the desired getStats IDL:
+    //  [CallWith=ScriptState] Promise<void> getStats(RTCStatsCallback successCallback, optional MediaStreamTrack? selector);
+    //  [CallWith=ScriptState] Promise<RTCStatsReport> getStats(optional MediaStreamTrack? selector);
+    // But the generated V8 bindings code is unable to distinguish between the
+    // two cases (e.g. single argument case always calls the MediaStreamTrack
+    // version). As a workaround, in order to support both signatures
+    // |getStats(optional any)| is used. In RTCPeerConnection.cpp we dispatch to
+    // the correct |getStats| function based on value type. crbug.com/629068.
+    [CallWith=ScriptState] Promise getStats(optional any value);
+    [CallWith=ScriptState] Promise<void> getStats(RTCStatsCallback successCallback, MediaStreamTrack? selector);
 
     // https://w3c.github.io/webrtc-pc/#peer-to-peer-data-api
     // TODO(guidou): The label argument should have [TreatNullAs=EmptyString]