Fix event dispatching and window resizing in high-dpi mode.

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

 // 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.
 
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h"
 
 #include <X11/extensions/shape.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/Xatom.h>
 #include <X11/Xregion.h>
@@ skipping 1783 matching lines @@
       display::Screen::GetScreen()->GetDisplayNearestWindow(window());
   const display::Display display_dest =
       display::Screen::GetScreen()->GetDisplayNearestWindow(host->window());
   DCHECK_EQ(display_src.device_scale_factor(),
             display_dest.device_scale_factor());
   gfx::Vector2d offset = GetLocationOnNativeScreen() -
                          host->GetLocationOnNativeScreen();
   gfx::PointF location_in_pixel_in_host =
       located_event->location_f() + gfx::Vector2dF(offset);
   located_event->set_location_f(location_in_pixel_in_host);
+  located_event->set_root_location_f(location_in_pixel_in_host);

[rjkroege, 2016/10/10 20:49:31]

is set_root_location_f in DIP or DDP? In screen space? event.h doesn't say. But
probably should (maybe in a different CL?)

[sadrul, 2016/10/11 15:13:37]

crbug.com/608547 is for this specific case, to replace 'root location' with a
'system location', and better define what exactly it means. For now,
unfortunately, this 'root location' can be in physical pixel space in some
places (e.g. immediately when the event is created from a native event), and in
DIP in other places (e.g. during the dispatch phase). So there isn't a good way
to clarify this with a comment in event.h

In this specific case, however, the event location is in physical pixel space
(which is why the local var-name has '_in_pixel_' in it)

 }
 
 void DesktopWindowTreeHostX11::ResetWindowRegion() {
   // If a custom window shape was supplied then apply it.
   if (custom_window_shape_) {
     XShapeCombineRegion(xdisplay_, xwindow_, ShapeBounding, 0, 0,
                         window_shape_.get(), false);
     return;
   }
 
@@ skipping 533 matching lines @@
   if (linux_ui) {
     ui::NativeTheme* native_theme = linux_ui->GetNativeTheme(window);
     if (native_theme)
       return native_theme;
   }
 
   return ui::NativeThemeAura::instance();
 }
 
 }  // namespace views