[Media Router] Add experiment control logic.

chrome/test/media_router/media_router_base_browsertest.cc

 // Copyright 2015 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.
 
 #include "chrome/test/media_router/media_router_base_browsertest.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/path_service.h"
 #include "base/timer/elapsed_timer.h"
@@ skipping 10 matching lines @@
 // Command line argument to specify CRX extension location.
 const char kExtensionCrx[] = "extension-crx";
 // Command line argument to specify unpacked extension location.
 const char kExtensionUnpacked[] = "extension-unpacked";
 }  // namespace
 
 
 namespace media_router {
 
 MediaRouterBaseBrowserTest::MediaRouterBaseBrowserTest()
-    : extension_load_event_(false, false), extension_host_created_(false) {
-  base::CommandLine::ForCurrentProcess()->AppendSwitch(
-      switches::kEnableMediaRouter);
+    : extension_load_event_(false, false),
+      extension_host_created_(false),
+      feature_override_(extensions::FeatureSwitch::media_router(), true) {
   base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
       switches::kEnableExperimentalWebPlatformFeatures, "Presentation");
 }
 
 MediaRouterBaseBrowserTest::~MediaRouterBaseBrowserTest() {
 }
 
 void MediaRouterBaseBrowserTest::SetUp() {
   ParseCommandLine();
   ExtensionBrowserTest::SetUp();
@@ skipping 85 matching lines @@
     if (PathExists(extension_path)) {
       extension_unpacked_ = extension_path;
     }
   }
 
   // Exactly one of these two arguments should be provided.
   ASSERT_NE(extension_crx_.empty(), extension_unpacked_.empty());
 }
 
 }  // namespace media_router