mus: Implement ScreenMus::GetCursorScreenPoint().

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

 // 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.
 
 #ifndef COMPONENTS_MUS_PUBLIC_CPP_LIB_WINDOW_TREE_CLIENT_IMPL_H_
 #define COMPONENTS_MUS_PUBLIC_CPP_LIB_WINDOW_TREE_CLIENT_IMPL_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <set>
 
+#include "base/atomicops.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "components/mus/common/types.h"
 #include "components/mus/public/cpp/window.h"
 #include "components/mus/public/cpp/window_manager_delegate.h"
 #include "components/mus/public/cpp/window_tree_connection.h"
 #include "components/mus/public/interfaces/window_tree.mojom.h"
 #include "mojo/public/cpp/bindings/associated_binding.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
 
 namespace gfx {
@@ skipping 131 matching lines @@
   Window* NewWindowImpl(NewWindowType type,
                         const Window::SharedProperties* properties);
 
   // OnEmbed() calls into this. Exposed as a separate function for testing.
   void OnEmbedImpl(mojom::WindowTree* window_tree,
                    ConnectionSpecificId connection_id,
                    mojom::WindowDataPtr root_data,
                    Id focused_window_id,
                    bool drawn);
 
+  void OnReceivedCursorLocationMemory(mojo::ScopedSharedBufferHandle handle);
+
   // Overridden from WindowTreeConnection:
   void SetDeleteOnNoRoots(bool value) override;
   const std::set<Window*>& GetRoots() override;
   Window* GetFocusedWindow() override;
   void ClearFocus() override;
+  void InitializeCursorLocation() override;
+  gfx::Point GetCursorScreenPoint() override;
   Window* NewWindow(const Window::SharedProperties* properties) override;
   Window* NewTopLevelWindow(
       const Window::SharedProperties* properties) override;
   ConnectionSpecificId GetConnectionId() override;
   void AddObserver(WindowTreeConnectionObserver* observer) override;
   void RemoveObserver(WindowTreeConnectionObserver* observer) override;
 
   // Overridden from WindowTreeClient:
   void OnEmbed(ConnectionSpecificId connection_id,
                mojom::WindowDataPtr root,
@@ skipping 106 matching lines @@
   mojo::Binding<WindowTreeClient> binding_;
   mojom::WindowTreePtr tree_ptr_;
   // Typically this is the value contained in |tree_ptr_|, but tests may
   // directly set this.
   mojom::WindowTree* tree_;
 
   bool delete_on_no_roots_;
 
   bool in_destructor_;
 
+  bool called_initialize_cursor_location_;

[sky, 2016/04/27 20:10:28]

Add comment.

+
+  // A handle to shared memory that is one 65 bit integer long. The window

[sky, 2016/04/27 20:10:28]

32?

+  // server uses this to let us synchronously read the cursor location.
+  mojo::ScopedSharedBufferHandle cursor_location_handle_;
+
+  // The one int in |cursor_location_handle_|. When we read from this
+  // location, we must always read from it atomically.
+  base::subtle::Atomic32* cursor_location_memory_;
+
   base::ObserverList<WindowTreeConnectionObserver> observers_;
 
   std::unique_ptr<mojo::AssociatedBinding<mojom::WindowManager>>
       window_manager_internal_;
   mojom::WindowManagerClientAssociatedPtr window_manager_internal_client_;
 
+  base::WeakPtrFactory<WindowTreeClientImpl> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowTreeClientImpl);
 };
 
 }  // namespace mus
 
 #endif  // COMPONENTS_MUS_PUBLIC_CPP_LIB_WINDOW_TREE_CLIENT_IMPL_H_