SetDeviceScaleFactorForTest

ui/views/widget/desktop_aura/desktop_window_tree_host_win.h

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
index 884df902ab268c4c677b125769eb257bd9cfb726..03076032efd3aa08429cc83eec7bb02de0ca672c 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
@@ -7,6 +7,7 @@
 
 #include "base/macros.h"
 #include "ui/aura/window_tree_host.h"
+#include "ui/display/display_observer.h"
 #include "ui/views/views_export.h"
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host.h"
 #include "ui/views/win/hwnd_message_handler_delegate.h"
@@ -33,6 +34,7 @@ class VIEWS_EXPORT DesktopWindowTreeHostWin
     : public DesktopWindowTreeHost,
       public aura::client::AnimationHost,
       public aura::WindowTreeHost,
+      public display::DisplayObserver,
       public HWNDMessageHandlerDelegate {
  public:
   DesktopWindowTreeHostWin(
@@ -127,6 +129,12 @@ class VIEWS_EXPORT DesktopWindowTreeHostWin
       const gfx::Vector2d& bottom_right_delta) override;
   void OnWindowHidingAnimationCompleted() override;
 
+  // display::DisplayObserver:
+  void OnDisplayAdded(const display::Display& display) override {}
+  void OnDisplayRemoved(const display::Display& display) override {}
+  void OnDisplayMetricsChanged(const display::Display& display,
+                               uint32_t changed_metrics) override;
+
   // Overridden from HWNDMessageHandlerDelegate:
   bool HasNonClientView() const override;
   FrameMode GetFrameMode() const override;