Show the Cast toolbar icon ephemerally when Cast is in use

chrome/common/pref_names.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.
 
 #include "chrome/common/pref_names.h"
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "chrome/common/pref_font_webkit_names.h"
 
@@ skipping 2216 matching lines @@
 const char kMediaRouterCloudServicesPrefSet[] =
     "media_router.cloudservices.prefset";
 // Whether or not the user has enabled cloud services with Media Router.
 const char kMediaRouterEnableCloudServices[] =
     "media_router.cloudservices.enabled";
 #endif  // defined(GOOGLE_CHROME_BUILD)
 // Whether or not the Media Router first run flow has been acknowledged by the
 // user.
 const char kMediaRouterFirstRunFlowAcknowledged[] =
     "media_router.firstrunflow.acknowledged";
-#endif
+const char kMediaRouterAlwaysShowActionIcon[] =
+    "media_router.action.always_show";
+#endif  // defined(ENABLE_MEDIA_ROUTER)
 
 // The base64-encoded representation of the public key to use to validate origin
 // trial token signatures.
 const char kOriginTrialPublicKey[] = "origin_trials.public_key";
 
 // A list of origin trial features to disable by policy.
 const char kOriginTrialDisabledFeatures[] = "origin_trials.disabled_features";
 
 }  // namespace prefs