Add a policy to always show the Cast toolbar icon

chrome/browser/ui/toolbar/media_router_action_controller.h

Index: chrome/browser/ui/toolbar/media_router_action_controller.h
diff --git a/chrome/browser/ui/toolbar/media_router_action_controller.h b/chrome/browser/ui/toolbar/media_router_action_controller.h
index d2bfda782ce451d7fe60a21c9abe0a6fba2e1abd..d1743a10bd2bab88f29ba7f7f5789b01b59130d4 100644
--- a/chrome/browser/ui/toolbar/media_router_action_controller.h
+++ b/chrome/browser/ui/toolbar/media_router_action_controller.h
@@ -12,6 +12,7 @@
 #include "chrome/browser/media/router/media_routes_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/prefs/pref_change_registrar.h"
+#include "components/user_prefs/user_prefs.h"
 
 using extensions::ComponentMigrationHelper;
 
@@ -31,6 +32,9 @@ class MediaRouterActionController : public media_router::IssuesObserver,
       ComponentMigrationHelper* component_migration_helper);
   ~MediaRouterActionController() override;
 
+  // Whether the media router action is shown by an administrator policy.
+  static bool IsActionShownByPolicy(content::BrowserContext* context);

[imcheng, 2016/12/15 19:57:38]

might as well use Profile here? Then you can do profile->GetPrefs() in the .cc.

[takumif, 2016/12/15 22:04:14]

Done.

+
   // media_router::IssuesObserver:
   void OnIssueUpdated(const media_router::Issue* issue) override;
 
@@ -76,6 +80,9 @@ class MediaRouterActionController : public media_router::IssuesObserver,
   bool has_issue_ = false;
   bool has_local_display_route_ = false;
 
+  // Whether the media router action is shown by an administrator policy.
+  bool shown_by_policy_;
+
   // The number of dialogs that are currently open.
   size_t dialog_count_ = 0;