HTMLMediaElement capture: teach the captured MStream to follow up source events

third_party/WebKit/Source/modules/mediastream/MediaStream.cpp

Index: third_party/WebKit/Source/modules/mediastream/MediaStream.cpp
diff --git a/third_party/WebKit/Source/modules/mediastream/MediaStream.cpp b/third_party/WebKit/Source/modules/mediastream/MediaStream.cpp
index f5051bf0020157220acc10fe724094714c2003ec..410b03092f488aa77beab5017733ba302aa00474 100644
--- a/third_party/WebKit/Source/modules/mediastream/MediaStream.cpp
+++ b/third_party/WebKit/Source/modules/mediastream/MediaStream.cpp
@@ -331,7 +331,7 @@ const AtomicString& MediaStream::interfaceName() const {
   return EventTargetNames::MediaStream;
 }
 
-void MediaStream::addRemoteTrack(MediaStreamComponent* component) {
+void MediaStream::addTrackByComponent(MediaStreamComponent* component) {
   DCHECK(component);
   if (!getExecutionContext())
     return;
@@ -358,7 +358,7 @@ void MediaStream::addRemoteTrack(MediaStreamComponent* component) {
   }
 }
 
-void MediaStream::removeRemoteTrack(MediaStreamComponent* component) {
+void MediaStream::removeTrackByComponent(MediaStreamComponent* component) {

[haraken, 2017/03/06 18:37:29]

I'm just curious: What happens if ExecutionContext gets detached after we called
addTrackByComponent but before we call removeTrackByComponent? Then
getExecutionContext() will return false at line 363 and thus the following code
won't run. Will it be okay?

[mcasas, 2017/03/06 19:38:59]

I'm not sure what the original developers intended,
perhaps we should also destroy the MediaStream if
and when the context is lost, but we are not a 
ContextLifecycleObserver, so I guess we're fine just
doing nothing?  
+guidou@ any thoughts?

   DCHECK(component);
   if (!getExecutionContext())
     return;