content: Remove views dependency.

ui/views/mus/native_widget_mus.cc

Index: ui/views/mus/native_widget_mus.cc
diff --git a/ui/views/mus/native_widget_mus.cc b/ui/views/mus/native_widget_mus.cc
index 31a680259d7b3005a3c2ff57422e5f0b1cf9db0e..4dcf0781044ab1d99a08d67aee78a4321df1ebcb 100644
--- a/ui/views/mus/native_widget_mus.cc
+++ b/ui/views/mus/native_widget_mus.cc
@@ -27,6 +27,7 @@
 #include "ui/aura/window.h"
 #include "ui/aura/window_property.h"
 #include "ui/base/hit_test.h"
+#include "ui/base/view_prop.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/events/event.h"
@@ -532,6 +533,9 @@ NativeWidgetMus::NativeWidgetMus(internal::NativeWidgetDelegate* delegate,
   }
 
   window_tree_host_.reset(new WindowTreeHostMus(this, window_));
+  prop_.reset(new ui::ViewProp(window_tree_host_->GetAcceleratedWidget(),
+                               ui::kWindowForAcceleratedWidget,
+                               window_));
   aura::Env::GetInstance()->set_context_factory(default_context_factory);
 }