Moves management of transients out of Window

ui/views/corewm/tooltip_controller_unittest.cc

Index: ui/views/corewm/tooltip_controller_unittest.cc
diff --git a/ui/views/corewm/tooltip_controller_unittest.cc b/ui/views/corewm/tooltip_controller_unittest.cc
index 6ebf4b9f8283111ed79eff3c40d3c8e5cc4bb4f8..f784a752480ef30f81cd40768deeca27b5a13287 100644
--- a/ui/views/corewm/tooltip_controller_unittest.cc
+++ b/ui/views/corewm/tooltip_controller_unittest.cc
@@ -23,6 +23,7 @@
 #include "ui/gfx/text_elider.h"
 #include "ui/views/corewm/tooltip_aura.h"
 #include "ui/views/corewm/tooltip_controller_test_helper.h"
+#include "ui/views/corewm/transient_window_stacking_client.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/tooltip_manager.h"
 #include "ui/views/widget/widget.h"
@@ -72,6 +73,10 @@ class TooltipControllerTest : public aura::test::AuraTestBase {
   virtual ~TooltipControllerTest() {}
 
   virtual void SetUp() OVERRIDE {
+    // SetWindowStackingClient() takes ownership of
+    // TransientWindowStackingClient.
+    aura::client::SetWindowStackingClient(
+        new corewm::TransientWindowStackingClient);
     aura::test::AuraTestBase::SetUp();
 #if defined(OS_CHROMEOS)
     controller_.reset(new TooltipController(