Moves TransientWindowClient to ui/aura/client and adds observer

ui/views/test/test_views_delegate.h

Index: ui/views/test/test_views_delegate.h
diff --git a/ui/views/test/test_views_delegate.h b/ui/views/test/test_views_delegate.h
index 5d756bc6a6e0c27c9dcd5e95f7acbaab3c0d2119..e1986ab37bf39b21505bacf3a401f84bab6148cb 100644
--- a/ui/views/test/test_views_delegate.h
+++ b/ui/views/test/test_views_delegate.h
@@ -11,10 +11,6 @@
 #include "build/build_config.h"
 #include "ui/views/views_delegate.h"
 
-namespace wm {
-class WMState;
-}
-
 namespace views {
 
 class TestViewsDelegate : public ViewsDelegate {
@@ -51,10 +47,6 @@ class TestViewsDelegate : public ViewsDelegate {
   bool use_desktop_native_widgets_;
   bool use_transparent_windows_;
 
-#if defined(USE_AURA)
-  std::unique_ptr<wm::WMState> wm_state_;
-#endif
-
   DISALLOW_COPY_AND_ASSIGN(TestViewsDelegate);
 };