Make PrefService available in *ash

ash/test/test_shell_delegate.cc

Index: ash/test/test_shell_delegate.cc
diff --git a/ash/test/test_shell_delegate.cc b/ash/test/test_shell_delegate.cc
index 5d75697439d8f5699efe230ffa9cd8bd4a3ef4f3..e6fc398f211ead96dfdb57bbc5c808272cab22cd 100644
--- a/ash/test/test_shell_delegate.cc
+++ b/ash/test/test_shell_delegate.cc
@@ -25,6 +25,8 @@
 #include "ash/wm_window.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "components/prefs/pref_service.h"
+#include "components/prefs/testing_pref_service.h"
 #include "ui/aura/window.h"
 #include "ui/gfx/image/image.h"
 
@@ -58,7 +60,8 @@ TestShellDelegate::TestShellDelegate()
     : num_exit_requests_(0),
       multi_profiles_enabled_(false),
       force_maximize_on_first_run_(false),
-      touchscreen_enabled_in_local_pref_(true) {}
+      touchscreen_enabled_in_local_pref_(true),
+      pref_service_(base::MakeUnique<TestingPrefServiceSimple>()) {}
 
 TestShellDelegate::~TestShellDelegate() {}
 
@@ -147,6 +150,10 @@ gfx::Image TestShellDelegate::GetDeprecatedAcceleratorImage() const {
   return gfx::Image();
 }
 
+PrefService* TestShellDelegate::GetActiveUserPrefService() const {
+  return pref_service_.get();
+}
+
 bool TestShellDelegate::IsTouchscreenEnabledInPrefs(
     bool use_local_state) const {
   return use_local_state ? touchscreen_enabled_in_local_pref_ : true;