Fixed tab dragging which was broken on high DPI windows for scales other than 100%.

ui/app_list/views/apps_grid_view.cc

Index: ui/app_list/views/apps_grid_view.cc
diff --git a/ui/app_list/views/apps_grid_view.cc b/ui/app_list/views/apps_grid_view.cc
index 470632df054073e925dd4786d958cb2e5b054838..49acb9a9aac1c1ee1c27282c9290eda8fc1b2f7d 100644
--- a/ui/app_list/views/apps_grid_view.cc
+++ b/ui/app_list/views/apps_grid_view.cc
@@ -46,6 +46,7 @@
 #include "ui/base/dragdrop/drop_target_win.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/base/dragdrop/os_exchange_data_provider_win.h"
+#include "ui/gfx/win/dpi.h"
 #endif
 
 namespace app_list {
@@ -294,6 +295,7 @@ class SynchronousDrag : public ui::DragSourceWin {
     GetCursorPos(&p);
     ScreenToClient(GetGridViewHWND(), &p);
     gfx::Point grid_view_pt(p.x, p.y);
+    grid_view_pt = gfx::win::ScreenToDIPPoint(grid_view_pt);
     views::View::ConvertPointFromWidget(grid_view_, &grid_view_pt);
     return grid_view_pt;
   }