Add methods to the content renderer client that allow for overriding WebRTC related objects

Use those methods to instantiate WebRTC mocks for layout tests in content_shell

BUG=111316
[email protected],[email protected]
TEST=more fast/mediastream tests pass

Review URL: https://codereview.chromium.org/12283012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@183093 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index f609bdb..6d8ac9f8 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -330,7 +330,7 @@
   scoped_ptr<RendererWebKitPlatformSupportImpl> webkit_platform_support_;
 
   // Used on the render thread and deleted by WebKit at shutdown.
-  MediaStreamCenter* media_stream_center_;
+  WebKit::WebMediaStreamCenter* media_stream_center_;
 
   // Used on the renderer and IPC threads.
   scoped_refptr<DBMessageFilter> db_message_filter_;