Added a placeholder new media-internals page under a flag.

content/browser/renderer_host/render_process_host_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 893 matching lines @@
     switches::kDomAutomationController,
     switches::kEnableAccessibilityLogging,
     switches::kEnableBeginFrameScheduling,
     switches::kEnableBrowserInputController,
     switches::kEnableBrowserPluginForAllViewTypes,
     switches::kEnableDCHECK,
     switches::kEnableDelegatedRenderer,
     switches::kEnableEncryptedMedia,
     switches::kDisableLegacyEncryptedMedia,
     switches::kOverrideEncryptedMediaCanPlayType,
+    switches::kEnableNewMediaInternals,

[scherkus (not reviewing), 2013/07/19 01:58:49]

we only propagate switches to the render process if the render process needs
them

AFAICT since the code needing the switch is in the browser process (i.e.,
content/browser/media/media_internals_ui.cc), you shouldn't need this line

can you try removing and seeing if everything still works?

[Ty Overby, 2013/07/19 17:48:00]

Done.  

You were right.

     switches::kEnableExperimentalWebPlatformFeatures,
     switches::kEnableFixedLayout,
     switches::kEnableDeferredImageDecoding,
     switches::kEnableGPUServiceLogging,
     switches::kEnableGPUClientLogging,
     switches::kEnableGpuClientTracing,
     switches::kEnableGpuBenchmarking,
     switches::kEnableMemoryBenchmarking,
     switches::kEnableSkiaBenchmarking,
     switches::kEnableLogging,
@@ skipping 869 matching lines @@
     // Skip widgets in other processes.
     if (widgets[i]->GetProcess()->GetID() != GetID())
       continue;
 
     RenderViewHost* rvh = RenderViewHost::From(widgets[i]);
     rvh->UpdateWebkitPreferences(rvh->GetWebkitPreferences());
   }
 }
 
 }  // namespace content