[Media Router] Ensure the same FeatureSwitch is used for lifetime of the browser.

chrome/browser/media/router/media_router_feature.cc

Index: chrome/browser/media/router/media_router_feature.cc
diff --git a/chrome/browser/media/router/media_router_feature.cc b/chrome/browser/media/router/media_router_feature.cc
index 3491c43af96af3e241c76238da94eaca6ed2bbd4..f67d662360f5f98b9b902048406490f4afc78b3e 100644
--- a/chrome/browser/media/router/media_router_feature.cc
+++ b/chrome/browser/media/router/media_router_feature.cc
@@ -8,9 +8,6 @@
 #include "content/public/browser/browser_context.h"
 
 #if defined(ENABLE_EXTENSIONS)
-#include "chrome/browser/extensions/api/tab_capture/tab_capture_api.h"
-#include "extensions/browser/extension_registry.h"
-#include "extensions/common/extension_set.h"
 #include "extensions/common/feature_switch.h"
 #endif
 
@@ -21,22 +18,6 @@ bool MediaRouterEnabled(content::BrowserContext* context) {
 #if defined(OS_ANDROID)
   return true;
 #elif defined(ENABLE_EXTENSIONS)
-  extensions::ExtensionRegistry* registry =
-      extensions::ExtensionRegistry::Get(context);
-  if (!registry) {
-    DLOG(ERROR) << "ExtensionRegistry is null. Assume no cast extension "
-                   "installed.";
-    return extensions::FeatureSwitch::media_router()->IsEnabled();
-  }
-
-  const extensions::ExtensionSet& extension_set =
-      registry->enabled_extensions();
-  if (extension_set.Contains(extensions::kStableChromecastExtensionId) ||
-      extension_set.Contains(extensions::kBetaChromecastExtensionId)) {
-    return extensions::FeatureSwitch::media_router_with_cast_extension()
-        ->IsEnabled();
-  }
-
   return extensions::FeatureSwitch::media_router()->IsEnabled();
 #else  // !defined(ENABLE_EXTENSIONS)
   return false;