[Media Router] Add experiment control logic.

chrome/browser/extensions/external_component_loader.cc

Index: chrome/browser/extensions/external_component_loader.cc
diff --git a/chrome/browser/extensions/external_component_loader.cc b/chrome/browser/extensions/external_component_loader.cc
index 8bace512e06e1e3b2d79163c4868d3d677c276ed..33eb2b1c7bee1ebc64a9f61f9d24b21dd752939a 100644
--- a/chrome/browser/extensions/external_component_loader.cc
+++ b/chrome/browser/extensions/external_component_loader.cc
@@ -25,6 +25,10 @@
 #include "chrome/browser/ui/app_list/google_now_extension.h"
 #endif
 
+#if defined(ENABLE_MEDIA_ROUTER) && defined(GOOGLE_CHROME_BUILD)
+#include "chrome/browser/media/router/media_router_feature.h"
+#endif
+
 namespace extensions {
 
 ExternalComponentLoader::ExternalComponentLoader(Profile* profile)
@@ -50,7 +54,7 @@ void ExternalComponentLoader::StartLoading() {
 #endif
 
 #if defined(ENABLE_MEDIA_ROUTER) && defined(GOOGLE_CHROME_BUILD)

[msw, 2015/10/23 20:18:42]

Why don't other blocks check GOOGLE_CHROME_BUILD?

[imcheng, 2015/10/23 21:39:26]

The stable extension that would be downloaded here contains closed source
components. But for development purposes we can build the extension ourselves
and use it with Chromium and Media Router.

[msw, 2015/10/23 22:30:49]

Acknowledged.

-  if (switches::MediaRouterEnabled())
+  if (media_router::MediaRouterEnabled())
     AddExternalExtension(extension_misc::kMediaRouterStableExtensionId);
 #endif  // defined(ENABLE_MEDIA_ROUTER) && defined(GOOGLE_CHROME_BUILD)