Fix window positioning in high-DPI on Windows.

ui/views/widget/desktop_aura/desktop_screen_position_client.cc

Index: ui/views/widget/desktop_aura/desktop_screen_position_client.cc
diff --git a/ui/views/widget/desktop_aura/desktop_screen_position_client.cc b/ui/views/widget/desktop_aura/desktop_screen_position_client.cc
index 5b4dbc0fcc1572f370244d79ca6195a21ee8bd00..2c268b865051cd692a84924aab84254d47adfc23 100644
--- a/ui/views/widget/desktop_aura/desktop_screen_position_client.cc
+++ b/ui/views/widget/desktop_aura/desktop_screen_position_client.cc
@@ -5,8 +5,25 @@
 #include "ui/views/widget/desktop_aura/desktop_screen_position_client.h"
 
 #include "ui/aura/root_window.h"
+#include "ui/gfx/display.h"
+#include "ui/gfx/point_conversions.h"
+#include "ui/gfx/screen.h"
+
 #include "ui/views/widget/desktop_aura/desktop_native_widget_aura.h"
 
+namespace {
+
+gfx::Point GetOrigin(const aura::RootWindow* root_window) {
+  gfx::Point origin_in_pixels = root_window->GetHostOrigin();
+  aura::RootWindow* window = const_cast<aura::RootWindow*>(root_window);
+  float scale = gfx::Screen::GetScreenFor(window)->
+       GetDisplayNearestWindow(window).device_scale_factor();
+  return gfx::ToFlooredPoint(
+      gfx::ScalePoint(origin_in_pixels, 1 / scale));
+}
+
+}  // namespace
+
 namespace views {
 
 DesktopScreenPositionClient::DesktopScreenPositionClient() {
@@ -19,14 +36,14 @@ void DesktopScreenPositionClient::ConvertPointToScreen(
     const aura::Window* window, gfx::Point* point) {
   const aura::RootWindow* root_window = window->GetRootWindow();
   aura::Window::ConvertPointToTarget(window, root_window, point);
-  gfx::Point origin = root_window->GetHostOrigin();
+  gfx::Point origin = GetOrigin(root_window);
   point->Offset(origin.x(), origin.y());
 }
 
 void DesktopScreenPositionClient::ConvertPointFromScreen(
     const aura::Window* window, gfx::Point* point) {
   const aura::RootWindow* root_window = window->GetRootWindow();
-  gfx::Point origin = root_window->GetHostOrigin();
+  gfx::Point origin = GetOrigin(root_window);
   point->Offset(-origin.x(), -origin.y());
   aura::Window::ConvertPointToTarget(root_window, window, point);
 }
@@ -53,7 +70,7 @@ void DesktopScreenPositionClient::SetBounds(
     // The caller expects windows we consider "embedded" to be placed in the
     // screen coordinate system. So we need to offset the root window's
     // position (which is in screen coordinates) from these bounds.
-    gfx::Point host_origin = root->GetHostOrigin();
+    gfx::Point host_origin = GetOrigin(root);
     origin.Offset(-host_origin.x(), -host_origin.y());
     window->SetBounds(gfx::Rect(origin, bounds.size()));
     return;