Add {Lock,Unlock,Show,Hide}Cursor() to the window manager mojom.

services/ui/ws/cursor_state.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_STATE_H_
+#define SERVICES_UI_WS_CURSOR_STATE_H_
+
+#include <memory>
+
+#include "base/optional.h"
+#include "ui/base/cursor/cursor_data.h"
+
+namespace ui {
+namespace ws {
+
+class DisplayManager;
+
+// Owns all the state about if and how the cursor is displayed in mus.
+class CursorState {
+ public:
+  CursorState(DisplayManager* display_manager);

[sky, 2017/05/14 16:12:31]

explicit

+  ~CursorState();
+
+  // Sets the normal cursor which would be used if the window manager hasn't
+  // set an override cursor.
+  void SetCurrentWindowCursor(const ui::CursorData& cursor);
+
+  // When the cursor is locked, changes to the cursor are queued up. Queued
+  // changes are performed atomically when the cursor is unlocked.
+  void LockCursor();
+  void UnlockCursor();
+
+  // Whether the cursor is visible on the display.
+  void SetCursorVisible(bool visible);
+
+  // Sets a cursor globally, which overrides the per-window cursors.
+  void SetGlobalOverrideCursor(const base::Optional<ui::CursorData>& cursor);
+
+ private:
+  // A snapshot of the cursor state at a specific time.
+  class StateSnapshot;
+
+  // Synchronizes |current_state_| with all the platform displays.
+  void SetPlatformCursor();
+
+  // Contains are the displays we notify on cursor changes.
+  DisplayManager* display_manager_;
+
+  // Number of times LockCursor() has been invoked without a corresponding
+  // UnlockCursor().
+  int cursor_lock_count_ = 0u;

[sky, 2017/05/14 16:12:31]

You shouldn't need the 'u' here.

+
+  // The current state of the cursor.
+  std::unique_ptr<StateSnapshot> current_state_;
+
+  // The cursor state to restore when the cursor is unlocked.
+  std::unique_ptr<StateSnapshot> state_on_unlock_;
+
+  DISALLOW_COPY_AND_ASSIGN(CursorState);
+};
+
+}  // namespace ws
+}  // namespace ui
+
+#endif  // SERVICES_UI_WS_CURSOR_STATE_H_