Refactor Windows DPI Point, Rect, and Size for Multiple Monitor DPI Awareness

ui/gfx/display.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_DISPLAY_H_
 #define UI_GFX_DISPLAY_H_
 
 #include <stdint.h>
 
 #include "base/compiler_specific.h"
@@ skipping 40 matching lines @@
     TOUCH_SUPPORT_AVAILABLE,
     TOUCH_SUPPORT_UNAVAILABLE,
   };
 
   enum : int64_t { kInvalidDisplayID = -1 };
 
   // Creates a display with kInvalidDisplayID as default.
   Display();
   explicit Display(int64_t id);
   Display(int64_t id, const Rect& bounds);
-  ~Display();
+  virtual ~Display();

[oshima, 2016/01/15 18:26:03]

Did you add subclass? I haven't look at other changes, but gfx::Display is
copyable by design, so it shouldn't have subclasses.

[robliao, 2016/01/15 19:28:16]

Yes, but it doesn't preclude copying. ScreenWin::DisplayWin maintains the
untransformed screen pixel bounds. I figured all outside uses of Display were
outbound of the Screen, so DisplayWin is fully contained within ScreenWin. When
a gfx::Display needs to be handed out, a DisplayWin is always copied to a
gfx::Display.

[oshima, 2016/01/15 19:55:53]

Style guide recommends to avoid it, and even if it works now, I still want to
avoid it because it's error prone.
Looks like you just want to remember physical bounds inside ScreenWin. Can you
just keep the mapping inside it?

 
   // Returns the forced device scale factor, which is given by
   // "--force-device-scale-factor".
   static float GetForcedDeviceScaleFactor();
 
   // Indicates if a device scale factor is being explicitly enforced from the
   // command line via "--force-device-scale-factor".
   static bool HasForceDeviceScaleFactor();
 
   // Resets the caches used to determine if a device scale factor is being
@@ skipping 78 matching lines @@
   Rect bounds_;
   Rect work_area_;
   float device_scale_factor_;
   Rotation rotation_;
   TouchSupport touch_support_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_DISPLAY_H_