Removing singleton property of MediaStreamManager and creating thread first when needed.

content/browser/resource_context.cc

Index: content/browser/resource_context.cc
diff --git a/content/browser/resource_context.cc b/content/browser/resource_context.cc
index efb73cd3a0fe842f415517c259668e66edc21d3e..874a150baa4715ff1689c71e52b7dfa231ca2d80 100644
--- a/content/browser/resource_context.cc
+++ b/content/browser/resource_context.cc
@@ -19,7 +19,8 @@ ResourceContext::ResourceContext()
       blob_storage_context_(NULL),
       quota_manager_(NULL),
       host_zoom_map_(NULL),
-      media_observer_(NULL) {
+      media_observer_(NULL),
+      media_stream_manager_(NULL) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 }
 
@@ -145,6 +146,19 @@ void ResourceContext::set_media_observer(MediaObserver* media_observer) {
   media_observer_ = media_observer;
 }
 
+media_stream::MediaStreamManager*
+ResourceContext::media_stream_manager() const {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  EnsureInitialized();
+  return media_stream_manager_;
+}
+
+void ResourceContext::set_media_stream_manager(
+    media_stream::MediaStreamManager* media_stream_manager) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  media_stream_manager_ = media_stream_manager;
+}
+
 const base::Callback<prerender::PrerenderManager*(void)>&
 ResourceContext::prerender_manager_getter() const {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));