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

services/ui/ws/event_dispatcher_delegate.h

Index: services/ui/ws/event_dispatcher_delegate.h
diff --git a/services/ui/ws/event_dispatcher_delegate.h b/services/ui/ws/event_dispatcher_delegate.h
index 69b7a1b40ee9d39917bf6703ce2d321111ae48c1..52961799b507e1e6dd66b14cbe51b13304b06479 100644
--- a/services/ui/ws/event_dispatcher_delegate.h
+++ b/services/ui/ws/event_dispatcher_delegate.h
@@ -55,7 +55,8 @@ class EventDispatcherDelegate {
   virtual void OnCaptureChanged(ServerWindow* new_capture,
                                 ServerWindow* old_capture) = 0;
 
-  virtual void OnMouseCursorLocationChanged(const gfx::Point& point) = 0;
+  virtual void OnMouseCursorLocationChanged(const gfx::Point& point,
+                                            const int64_t display_id) = 0;
 
   // Dispatches an event to the specific client.
   virtual void DispatchInputEventToWindow(ServerWindow* target,
@@ -69,10 +70,12 @@ class EventDispatcherDelegate {
                                                   bool in_nonclient_area) = 0;
 
   // Returns the window to start searching from at the specified location, or
-  // null if there is a no window containing |location|. |location| should be in
-  // screen coordinates and if a window is returned then |location| will be
-  // updated to be relative to the origin of the window.
-  virtual ServerWindow* GetRootWindowContaining(gfx::Point* location) = 0;
+  // null if there is a no window containing |location_in_display|.
+  // |location_in_display| should be in display coordinates and in pixels.
+  // |location_in_display| and |display_id| will be updated if the window we
+  // found is on a different display than the originated display.
+  virtual ServerWindow* GetRootWindowContaining(gfx::Point* location_in_display,
+                                                int64_t* display_id) = 0;
 
   // Called when event dispatch could not find a target. OnAccelerator may still
   // be called.