Convert //mash to define service names in mojom

ash/mus/keyboard_ui_mus.cc

Index: ash/mus/keyboard_ui_mus.cc
diff --git a/ash/mus/keyboard_ui_mus.cc b/ash/mus/keyboard_ui_mus.cc
index b52fe59518c239c06a73b8e03f490991f8caacf8..4a7f1ab264af2391f882ff16b68170592b9706c6 100644
--- a/ash/mus/keyboard_ui_mus.cc
+++ b/ash/mus/keyboard_ui_mus.cc
@@ -6,6 +6,7 @@
 
 #include "ash/common/keyboard/keyboard_ui_observer.h"
 #include "base/memory/ptr_util.h"
+#include "content/public/common/service_names.mojom.h"
 #include "services/service_manager/public/cpp/connector.h"
 
 namespace ash {
@@ -14,7 +15,8 @@ KeyboardUIMus::KeyboardUIMus(service_manager::Connector* connector)
     : is_enabled_(false), observer_binding_(this) {
   if (connector) {
     // TODO(sky): should be something like mojo:keyboard, but need mapping.
-    connector->ConnectToInterface("content_browser", &keyboard_);
+    connector->ConnectToInterface(content::mojom::kBrowserServiceName,
+                                  &keyboard_);
     keyboard_->AddObserver(observer_binding_.CreateInterfacePtrAndBind());
   }
 }