Create MediaRouterActionController and MediaRouterUIService

chrome/browser/extensions/component_migration_helper.cc

Index: chrome/browser/extensions/component_migration_helper.cc
diff --git a/chrome/browser/extensions/component_migration_helper.cc b/chrome/browser/extensions/component_migration_helper.cc
index 7de2caa9773e3e49033483107317284b888d23b4..ecfc443f785b8a879ef2add1602485db06b3e1a1 100644
--- a/chrome/browser/extensions/component_migration_helper.cc
+++ b/chrome/browser/extensions/component_migration_helper.cc
@@ -9,6 +9,7 @@
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system_impl.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/toolbar/component_toolbar_actions_factory.h"
 #include "chrome/common/pref_names.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
@@ -92,9 +93,14 @@ void ComponentMigrationHelper::OnFeatureEnabled(
     component_action_pref = true;
   }
 
-  if (component_action_pref &&
-      !delegate_->HasComponentAction(component_action_id)) {
-    delegate_->AddComponentAction(component_action_id);
+  if (component_action_pref) {

[mark a. foltz, 2016/09/09 17:48:28]

Just so I understand - this code is here to ensure that users with the extension
or a pre-existing |component_action_pref| force
prefs::kMediaRouterAlwaysShowActionIcon to true.

I think this makes sense; we want the "checked" status of the context menu item
to reflect that the action will remain in the toolbar.

However, since it's a syncable pref, this will effectively enable the action
across all of the user's profiles (even if they only had the extension on one of
them).

I think that's okay as well; I consider this to be an extension of the toolbar
model, which is also synced. 

+    if (component_action_id ==
+        ComponentToolbarActionsFactory::kMediaRouterActionId) {
+      pref_service_->SetBoolean(prefs::kMediaRouterAlwaysShowActionIcon,

[mark a. foltz, 2016/09/09 17:48:28]

Can this only be set if the current value is not already true?  I believe this
will write prefs to disk.

Suggest factoring out a function to check-and-set the pref.

+                                true);
+    }
+    if (!delegate_->HasComponentAction(component_action_id))
+      delegate_->AddComponentAction(component_action_id);
   }
 }
 
@@ -107,6 +113,12 @@ void ComponentMigrationHelper::OnFeatureDisabled(
   enabled_actions_.erase(component_action_id);
   RemoveComponentActionPref(component_action_id);
 
+  if (component_action_id ==

[mark a. foltz, 2016/09/09 17:48:28]

If the feature is disabled, we should not be creating the action at all, IIUC. I
would be okay with leaving the existing pref value for the next time the MR is
re-enabled.

+      ComponentToolbarActionsFactory::kMediaRouterActionId) {
+    pref_service_->SetBoolean(prefs::kMediaRouterAlwaysShowActionIcon,
+                              false);
+  }
+
   if (FeatureSwitch::extension_action_redesign()->IsEnabled() &&
       delegate_->HasComponentAction(component_action_id))
     delegate_->RemoveComponentAction(component_action_id);
@@ -134,6 +146,14 @@ void ComponentMigrationHelper::OnExtensionReady(
     UnloadExtension(extension_id);
     SetComponentActionPref(component_action_id, true);
 
+    // We treat installation of the cast extension as a signal to permanently
+    // show the icon in the toolbar.
+    if (component_action_id ==

[mark a. foltz, 2016/09/09 17:48:28]

Please check-and-set the pref.

+        ComponentToolbarActionsFactory::kMediaRouterActionId) {
+      pref_service_->SetBoolean(prefs::kMediaRouterAlwaysShowActionIcon,
+                                true);
+    }
+
     if (!delegate_->HasComponentAction(component_action_id))
       delegate_->AddComponentAction(component_action_id);
   }