Refactor X11ForeignWindowManager (Reland)

ui/base/x/x11_window_event_manager.h

Index: ui/base/x/x11_window_event_manager.h
diff --git a/ui/base/x/x11_window_event_manager.h b/ui/base/x/x11_window_event_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..0ac5a5f96c7b5517ca3c7947bc9911ef74b72189
--- /dev/null
+++ b/ui/base/x/x11_window_event_manager.h
@@ -0,0 +1,73 @@
+// Copyright 2016 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 UI_BASE_X_X11_WINDOW_EVENT_MANAGER_H_
+#define UI_BASE_X_X11_WINDOW_EVENT_MANAGER_H_
+
+#include <map>
+#include <vector>
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "ui/base/x/ui_base_x_export.h"
+#include "ui/gfx/x/x11_types.h"
+
+// A process wide singleton for selecting events on X windows which were not
+// created by Chrome.
+namespace base {
+template <typename T>
+struct DefaultSingletonTraits;
+}
+
+namespace ui {
+
+// Ensures events in |event_mask| are selected on |xid| for the duration of this
+// object's lifetime.
+class UI_BASE_X_EXPORT XScopedEventSelector {
+ public:
+  XScopedEventSelector(XID xid, uint32_t event_mask);
+  ~XScopedEventSelector();
+
+ private:
+  XID xid_;
+  uint32_t event_mask_;
+
+  DISALLOW_COPY_AND_ASSIGN(XScopedEventSelector);
+};
+
+// Manages the events that Chrome has selected on X windows which were not
+// created by Chrome. This class allows multiple clients within Chrome to select
+// events on the same X window.
+class UI_BASE_X_EXPORT XWindowEventManager {
+ public:
+  static XWindowEventManager* GetInstance();
+
+ private:
+  friend struct base::DefaultSingletonTraits<XWindowEventManager>;
+  friend class XScopedEventSelector;
+
+  class MultiMask;
+
+  XWindowEventManager();
+  ~XWindowEventManager();
+
+  // Guarantees that events in |event_mask| will be reported to Chrome.
+  void SelectEvents(XID xid, uint32_t event_mask);
+
+  // Deselects events on |event_mask|.  Chrome will stop receiving events for
+  // any set bit in |event_mask| only if no other client has selected that bit.
+  void DeselectEvents(XID xid, uint32_t event_mask);
+
+  // Called whenever the mask corresponding to window |xid| might have changed.
+  // Updates the event mask with respect to the server, if necessary.
+  void AfterMaskChanged(XID xid, uint32_t old_mask);
+
+  std::map<XID, std::unique_ptr<MultiMask>> mask_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(XWindowEventManager);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_X_X11_FOREIGN_WINDOW_MANAGER_H_