Add a policy to always show the Cast toolbar icon

chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc

Index: chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc
diff --git a/chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc b/chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc
index 487a59a88d9ba57f538fb13f71c930c0a21db8ee..365c41a6836147bf5a560ff1a0764e5de2a87db9 100644
--- a/chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc
+++ b/chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc
@@ -10,6 +10,7 @@
 #include "chrome/browser/media/router/media_router_feature.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/toolbar/media_router_action_controller.h"
 #include "chrome/browser/ui/toolbar/toolbar_action_view_controller.h"
 #include "extensions/common/feature_switch.h"
 
@@ -44,6 +45,8 @@ ComponentToolbarActionsFactory* ComponentToolbarActionsFactory::GetInstance() {
 std::set<std::string> ComponentToolbarActionsFactory::GetInitialComponentIds(
     Profile* profile) {
   std::set<std::string> component_ids;
+  if (MediaRouterActionController::IsActionShownByPolicy(profile))

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

Seems like we also need to check media_router::MediaRouterEnabled()?

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

Yes, we should. Done.

+    component_ids.insert(kMediaRouterActionId);
   return component_ids;
 }