Add a policy to always show the Cast toolbar icon

chrome/common/pref_names.h

 // 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.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 
 #include <stddef.h>
@@ skipping 719 matching lines @@
 extern const char kFactoryResetRequested[];
 extern const char kDebuggingFeaturesRequested[];
 
 #if defined(OS_CHROMEOS)
 extern const char kResolveDeviceTimezoneByGeolocation[];
 extern const char kSystemTimezoneAutomaticDetectionPolicy[];
 #endif  // defined(OS_CHROMEOS)
 
 #if defined(ENABLE_MEDIA_ROUTER)
 extern const char kEnableMediaRouter[];
+#if !defined(OS_ANDROID)
+extern const char kShowCastIconInToolbar[];
+#endif  // !defined(OS_ANDROID)
 #endif  // defined(ENABLE_MEDIA_ROUTER)
 
 #if !defined(OS_ANDROID)
 extern const char kAttemptedToEnableAutoupdate[];
 
 extern const char kMediaGalleriesUniqueId[];
 extern const char kMediaGalleriesRememberedGalleries[];
 #endif  // !defined(OS_ANDROID)
 
 #if defined(USE_AURA)
@@ skipping 118 matching lines @@
 extern const char kSearchGeolocationDisclosureLastShowDate[];
 extern const char kSearchGeolocationPreDisclosureMetricsRecorded[];
 extern const char kSearchGeolocationPostDisclosureMetricsRecorded[];
 #endif
 
 extern const char kGoogleDSEGeolocationSetting[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_