Keep root_location to be in pixels and display coordinates in WS.

services/ui/ws/platform_display_default.cc

 // Copyright 2016 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 "services/ui/ws/platform_display_default.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "gpu/ipc/client/gpu_channel_host.h"
@@ skipping 161 matching lines @@
   if (frame_generator_) {
     frame_generator_->SetDeviceScaleFactor(metrics_.device_scale_factor);
     frame_generator_->OnWindowSizeChanged(metrics_.bounds_in_pixels.size());
   }
 }
 
 gfx::AcceleratedWidget PlatformDisplayDefault::GetAcceleratedWidget() const {
   return widget_;
 }
 
-void PlatformDisplayDefault::UpdateEventRootLocation(ui::LocatedEvent* event) {
-  // TODO(riajiang): This is broken for HDPI because it mixes PPs and DIPs. See
-  // http://crbug.com/701036 for details.
-  const display::Display& display = delegate_->GetDisplay();
-  gfx::Point location = event->location();
-  location.Offset(display.bounds().x(), display.bounds().y());
-  event->set_root_location(location);
-}
-
 void PlatformDisplayDefault::OnBoundsChanged(const gfx::Rect& new_bounds) {
   // We only care if the window size has changed.
   if (new_bounds.size() == metrics_.bounds_in_pixels.size())
     return;
 
   // TODO(tonikitoo): Handle the bounds changing in external window mode. The
   // window should be resized by the WS and it shouldn't involve ScreenManager.
 }
 
 void PlatformDisplayDefault::OnDamageRect(const gfx::Rect& damaged_region) {
   if (frame_generator_)
     frame_generator_->OnWindowDamaged();
 }
 
 void PlatformDisplayDefault::DispatchEvent(ui::Event* event) {
-  if (event->IsLocatedEvent())
-    UpdateEventRootLocation(event->AsLocatedEvent());
-
+  // Event location and event root location are the same, and both in pixels
+  // and display coordinates.
   if (event->IsScrollEvent()) {
     // TODO(moshayedi): crbug.com/602859. Dispatch scroll events as
     // they are once we have proper support for scroll events.
 
     ui::PointerEvent pointer_event(
         ui::MouseWheelEvent(*event->AsScrollEvent()));
     SendEventToSink(&pointer_event);
   } else if (event->IsMouseEvent()) {
     ui::PointerEvent pointer_event(*event->AsMouseEvent());
     SendEventToSink(&pointer_event);
@@ skipping 55 matching lines @@
 }
 
 void PlatformDisplayDefault::OnAcceleratedWidgetDestroyed() {
   NOTREACHED();
 }
 
 void PlatformDisplayDefault::OnActivationChanged(bool active) {}
 
 }  // namespace ws
 }  // namespace ui