Enable hidpi on Linux, refactor a bit on Windows to share

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 2c277a5e7404f3d74f1c7adac4787cdaa6ee3960..31ccb108ef06d828ea028e2fec0be28b39f104f8 100644
--- a/ui/app_list/views/apps_grid_view.cc
+++ b/ui/app_list/views/apps_grid_view.cc
@@ -24,6 +24,7 @@
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/events/event.h"
 #include "ui/gfx/animation/animation.h"
+#include "ui/gfx/dpi.h"
 #include "ui/gfx/geometry/vector2d.h"
 #include "ui/gfx/geometry/vector2d_conversions.h"
 #include "ui/views/border.h"
@@ -46,7 +47,6 @@
 #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 {
@@ -337,7 +337,7 @@ 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);
+    grid_view_pt = gfx::ScreenToDIPPoint(grid_view_pt);
     views::View::ConvertPointFromWidget(grid_view_, &grid_view_pt);
     return grid_view_pt;
   }