Make rendering of MediaStreams reflect changes to its set of tracks.

third_party/WebKit/Source/core/html/HTMLMediaElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
index 989a95832f849c1e1e2651401e4fadf91f907abd..3859e280f849936e99edab48d430f4c51b6f1aa1 100644
--- a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
@@ -780,6 +780,9 @@ void HTMLMediaElement::SetSrc(const AtomicString& url) {
 
 void HTMLMediaElement::SetSrcObject(MediaStreamDescriptor* src_object) {
   BLINK_MEDIA_LOG << "setSrcObject(" << (void*)this << ")";
+  if (src_object_ == src_object)

[foolip, 2017/07/05 08:49:44]

https://html.spec.whatwg.org/multipage/media.html#dom-media-srcobject says "On
setting, it must set the element's assigned media provider object to the new
value, and then invoke the element's media element load algorithm." with no
short-circuiting for when the value is the same. Is this a necessary part of the
fix?

[Guido Urdaneta, 2017/07/05 13:05:02]

Reverted the change and added a test to make sure the load algorithm runs when
reassigning the same object.

[foolip, 2017/07/05 13:13:52]

Great!

+    return;
+
   src_object_ = src_object;
   InvokeLoadAlgorithm();
 }