create a separate WebMediaPlayer for URL derived from media stream

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
===================================================================
--- content/renderer/render_view_impl.cc	(revision 155219)
+++ content/renderer/render_view_impl.cc	(working copy)
@@ -192,6 +192,7 @@
 #include "webkit/glue/weburlresponse_extradata_impl.h"
 #include "webkit/gpu/webgraphicscontext3d_in_process_impl.h"
 #include "webkit/media/webmediaplayer_impl.h"
+#include "webkit/media/webmediaplayer_ms.h"
 #include "webkit/plugins/npapi/plugin_list.h"
 #include "webkit/plugins/npapi/webplugin_delegate.h"
 #include "webkit/plugins/npapi/webplugin_delegate_impl.h"
@@ -2496,8 +2497,7 @@
   }
 
   WebGraphicsContext3DCommandBufferImpl* context3d = NULL;
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kDisableAcceleratedVideoDecode))
+  if (!cmd_line->HasSwitch(switches::kDisableAcceleratedVideoDecode))
     context3d = RenderThreadImpl::current()->GetGpuVDAContext3D();
   if (context3d) {
     scoped_refptr<base::MessageLoopProxy> factories_loop =
@@ -2523,6 +2523,15 @@
           audio_source_provider, message_loop_factory, media_stream_impl_,
           render_media_log);
   if (!media_player) {
+    EnsureMediaStreamImpl();

[piman, 2012/09/22 01:03:37]

This looks heavy the first time (e.g. it creates a thread), but we'll pay that
cost even if the flag isn't set / it's not a media stream url.
Looking at IsMediaStream, it looks like it doesn't need anything from
MediaStreamImpl and could be implemented as a static method, so that you could
do this only the first time you need to create a WebMediaPlayerMS. WDYT?

[wjia(left Chromium), 2012/09/22 17:04:42]

That's a good point. In MediaStreamImpl, IsMediaStream doesn't need anything
from MediaStreamImpl. However, it uses GetMediaStream which is a virtual
function for test purpose
(http://code.google.com/p/chromium/source/search?q=getmediastream&origq=getmed...).
The unit test (in media_stream_impl_unittest.cc) has a different implementation
of GetMediaStream and it uses some member. It will be some refactoring effort to
make IsStreamMedia static. Could we do it in a follow-up patch?

For now, I changed the condition checking a bit so that it won't affect chrome
performance when the flag is not on.

+    if (cmd_line->HasSwitch(switches::kEnableWebMediaPlayerMS) &&
+        media_stream_impl_ && media_stream_impl_->IsMediaStream(url)) {
+      // TODO(wjia): when all patches related to WebMediaPlayerMS have been
+      // landed, remove the switch. Refer to crbug.com/142988.
+      return new webkit_media::WebMediaPlayerMS(
+          frame, client, AsWeakPtr(), media_stream_impl_, render_media_log);
+    }
+
     media_player = new webkit_media::WebMediaPlayerImpl(
         frame, client, AsWeakPtr(), collection, audio_source_provider,
         audio_source_provider, message_loop_factory, media_stream_impl_,