[Media Router] Custom Controls 3 - add plumbing through MRUI and MRWebUIMessageHandler

chrome/common/chrome_features.cc

Index: chrome/common/chrome_features.cc
diff --git a/chrome/common/chrome_features.cc b/chrome/common/chrome_features.cc
index 3949411d8017577a9bb1f6dcbf7f27590ad778d0..9cf55d41af43429058389584c2c2daa29096b11f 100644
--- a/chrome/common/chrome_features.cc
+++ b/chrome/common/chrome_features.cc
@@ -205,6 +205,12 @@ const base::Feature kMediaRemoting{"MediaRemoting",
                                    base::FEATURE_DISABLED_BY_DEFAULT};
 const base::Feature kMediaRemotingEncrypted{"MediaRemotingEncrypted",
                                             base::FEATURE_DISABLED_BY_DEFAULT};
+
+// If enabled, replaces the <extensionview> controller in the route details view
+// of the Media Router dialog with the controller bundled with the WebUI
+// resources.
+const base::Feature kMediaRouterUIRouteController{
+    "MediaRouterUIRouteController", base::FEATURE_DISABLED_BY_DEFAULT};
 #endif  // !defined(OS_ANDROID) && !defined(OS_IOS)
 
 // Enables or disables modal permission prompts.