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

services/ui/ws/cursor_location_manager.h

 // Copyright 2017 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.
 
 #ifndef SERVICES_UI_WS_CURSOR_LOCATION_MANAGER_H_
 #define SERVICES_UI_WS_CURSOR_LOCATION_MANAGER_H_
 
 #include "base/atomicops.h"
 #include "base/macros.h"
 #include "mojo/public/cpp/system/buffer.h"
 
 namespace gfx {
 class Point;
 }
 
 namespace ui {
 namespace ws {
 
 // Manages a shared memory buffer that stores the cursor location.
 class CursorLocationManager {
  public:
   CursorLocationManager();
   ~CursorLocationManager();
 
   // Sets the current cursor location to |point|. Atomically writes the location
-  // to shared memory.
+  // to shared memory. |point| should be in screen-coord and DIP.
   void OnMouseCursorLocationChanged(const gfx::Point& point);

[sky, 2017/05/25 22:10:19]

Please rename to point_in_dips to make that clear.

[riajiang, 2017/05/25 22:59:23]

Renamed to point_in_dip?

 
   // Returns a read-only handle to the shared memory which contains the global
   // mouse cursor position. Each call returns a new handle.
   mojo::ScopedSharedBufferHandle GetCursorLocationMemory();
 
  private:
   base::subtle::Atomic32* cursor_location_memory() {
     return reinterpret_cast<base::subtle::Atomic32*>(
         cursor_location_mapping_.get());
   }
@@ skipping 12 matching lines @@
   // mojo connection, this data must be read atomically.)
   mojo::ScopedSharedBufferMapping cursor_location_mapping_;
 
   DISALLOW_COPY_AND_ASSIGN(CursorLocationManager);
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_CURSOR_LOCATION_MANAGER_H_