MediaRecorder: make MediaRecorderHandler a MediaStreamObserver

content/renderer/media/media_stream.cc

Index: content/renderer/media/media_stream.cc
diff --git a/content/renderer/media/media_stream.cc b/content/renderer/media/media_stream.cc
index 27e61b914ed3f999ec6659c1f29a2e2d7acaebdd..30138dba3cdca8d16c398937e5db36db48344ff9 100644
--- a/content/renderer/media/media_stream.cc
+++ b/content/renderer/media/media_stream.cc
@@ -7,13 +7,12 @@
 #include <algorithm>
 
 #include "base/logging.h"
-#include "third_party/WebKit/public/platform/WebString.h"
 
 namespace content {
 
 // static
-MediaStream* MediaStream::GetMediaStream(
-    const blink::WebMediaStream& stream) {
+MediaStream* MediaStream::GetMediaStream(const blink::WebMediaStream& stream) {
+  DCHECK(stream.extraData());
   return static_cast<MediaStream*>(stream.extraData());
 }
 
@@ -21,7 +20,7 @@ MediaStream::MediaStream() {
 }
 
 MediaStream::~MediaStream() {
-  DCHECK(observers_.empty());
+  observers_.clear();
 }
 
 void MediaStream::AddObserver(MediaStreamObserver* observer) {