mus: Implement ScreenMus::GetCursorScreenPoint().

components/mus/public/cpp/lib/window_tree_client_impl.cc

 // Copyright 2014 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 "components/mus/public/cpp/lib/window_tree_client_impl.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
+#include "base/threading/thread_restrictions.h"
 #include "components/mus/common/util.h"
 #include "components/mus/public/cpp/input_event_handler.h"
 #include "components/mus/public/cpp/lib/in_flight_change.h"
 #include "components/mus/public/cpp/lib/window_private.h"
 #include "components/mus/public/cpp/window_manager_delegate.h"
 #include "components/mus/public/cpp/window_observer.h"
 #include "components/mus/public/cpp/window_tracker.h"
 #include "components/mus/public/cpp/window_tree_connection.h"
 #include "components/mus/public/cpp/window_tree_connection_observer.h"
 #include "components/mus/public/cpp/window_tree_delegate.h"
@@ skipping 785 matching lines @@
 void WindowTreeClientImpl::OnWindowDeleted(Id window_id) {
   Window* window = GetWindowByServerId(window_id);
   if (window)
     WindowPrivate(window).LocalDestroy();
 }
 
 Window* WindowTreeClientImpl::GetCaptureWindow() {
   return capture_window_;
 }
 
+gfx::Point WindowTreeClientImpl::GetCursorScreenPoint() {
+  base::ThreadRestrictions::ScopedAllowWait allow_wait;

[sky, 2016/04/18 15:09:11]

Add a TODO that this code should use the location from the current event if
we're in the process of dispatching one. We can't do that until James lands
https://codereview.chromium.org/1883263002/ .

+  mojo::PointPtr p;
+  tree_ptr_->GetCursorScreenPoint(&p);
+  return p.To<gfx::Point>();
+}
+
 void WindowTreeClientImpl::OnWindowVisibilityChanged(Id window_id,
                                                      bool visible) {
   Window* window = GetWindowByServerId(window_id);
   if (!window)
     return;
 
   InFlightVisibleChange new_change(window, visible);
   if (ApplyServerChangeToExistingInFlightChange(new_change))
     return;
 
@@ skipping 205 matching lines @@
 
 void WindowTreeClientImpl::SetUnderlaySurfaceOffsetAndExtendedHitArea(
     Window* window,
     const gfx::Vector2d& offset,
     const gfx::Insets& hit_area) {
   window_manager_internal_client_->SetUnderlaySurfaceOffsetAndExtendedHitArea(
       server_id(window), offset.x(), offset.y(), mojo::Insets::From(hit_area));
 }
 
 }  // namespace mus