Add a policy to always show the Cast toolbar icon

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index e4db80dd6500fd7fd03265a5c2171cc1e1d71d54..ca9d5edaa26d6a1becd688edaec24f3af31b6981 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1946,6 +1946,11 @@ const char kSystemTimezoneAutomaticDetectionPolicy[] =
 #if defined(ENABLE_MEDIA_ROUTER)
 // Pref name for the policy controlling whether to enable Media Router.
 const char kEnableMediaRouter[] = "media_router.enable_media_router";
+#if !defined(OS_ANDROID)
+// Pref name for the policy controlling whether to force the Cast icon to be
+// shown in the toolbar/overflow menu.
+const char kShowCastIconInToolbar[] = "media_router.show_cast_icon_in_toolbar";
+#endif  // !defined(OS_ANDROID)
 #endif  // defined(ENABLE_MEDIA_ROUTER)
 
 // *************** SERVICE PREFS ***************