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

ui/wm/core/default_screen_position_client.cc

Index: ui/wm/core/default_screen_position_client.cc
diff --git a/ui/wm/core/default_screen_position_client.cc b/ui/wm/core/default_screen_position_client.cc
index d26a91ed9c8f92c66495eab9cfc7de7e5a749d87..13021a3175611f1a72a18b4ee50573fbb4c3d59d 100644
--- a/ui/wm/core/default_screen_position_client.cc
+++ b/ui/wm/core/default_screen_position_client.cc
@@ -7,6 +7,7 @@
 #include "ui/aura/window_tree_host.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/geometry/point_conversions.h"
+#include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/screen.h"
 
 namespace wm {
@@ -19,11 +20,11 @@ DefaultScreenPositionClient::~DefaultScreenPositionClient() {
 
 gfx::Point DefaultScreenPositionClient::GetOriginInScreen(
     const aura::Window* root_window) {
-  gfx::Point origin_in_pixels = root_window->GetHost()->GetBounds().origin();
   aura::Window* window = const_cast<aura::Window*>(root_window);
-  float scale = gfx::Screen::GetScreenFor(window)->
-       GetDisplayNearestWindow(window).device_scale_factor();
-  return gfx::ScaleToFlooredPoint(origin_in_pixels, 1.0f / scale);
+  gfx::Screen* screen = gfx::Screen::GetScreenFor(window);
+  gfx::Rect screen_bounds = root_window->GetHost()->GetBounds();
+  gfx::Rect dip_bounds = screen->ScreenToDIPRectInWindow(window, screen_bounds);

[oshima, 2016/01/21 17:47:44]

is this screen_bounds in native screen coordinates?

[robliao, 2016/01/21 18:19:20]

We really need that units refactor.

GetOriginInScreen returns a Screen point in DIP units.
root_window->GetHost()->GetBounds() returns a rect in Screen coordinates in
physical pixel units (In Windows, it calls directly into GetClientRect + a
ClientToScreen call)

The conversion step turns it into screen coordinates + DIP units.

+  return dip_bounds.origin();
 }
 
 void DefaultScreenPositionClient::ConvertPointToScreen(