Enable media stream layout test with content_shell.

content/shell/webkit_test_runner.h

Index: content/shell/webkit_test_runner.h
===================================================================
--- content/shell/webkit_test_runner.h	(revision 191981)
+++ content/shell/webkit_test_runner.h	(working copy)
@@ -19,6 +19,8 @@
 class SkCanvas;
 
 namespace WebKit {
+class WebMediaPlayer;
+class WebMediaPlayerClient;
 struct WebRect;
 }
 
@@ -26,6 +28,10 @@
 class WebTestProxyBase;
 }
 
+namespace webkit_glue {
+class TestMediaStreamClient;
+}
+
 namespace content {
 
 // This is the renderer side of the webkit test runner.
@@ -90,6 +96,10 @@
       WebTestRunner::WebTestProxyBase* proxy,
       WebKit::WebVector<WebKit::WebHistoryItem>* history,
       size_t* currentEntryIndex);
+  virtual WebKit::WebMediaPlayer* createWebMediaPlayer(
+      WebKit::WebFrame* frame,
+      const WebKit::WebURL& url,
+      WebKit::WebMediaPlayerClient* client);
 
   void Reset();
 
@@ -125,6 +135,8 @@
 
   bool focus_on_next_commit_;
 
+  scoped_ptr<webkit_glue::TestMediaStreamClient> test_media_stream_client_;
+
   DISALLOW_COPY_AND_ASSIGN(WebKitTestRunner);
 };