Refactor X11ForeignWindowManager (Reland)

ui/base/x/x11_window_manager.h

Index: ui/base/x/x11_window_manager.h
diff --git a/ui/base/x/x11_window_manager.h b/ui/base/x/x11_window_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..db7e72e1630260b37d5fbecffe27ab2d0eaad64d
--- /dev/null
+++ b/ui/base/x/x11_window_manager.h
@@ -0,0 +1,70 @@
+// 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 UI_BASE_X_X11_FOREIGN_WINDOW_MANAGER_H_
+#define UI_BASE_X_X11_FOREIGN_WINDOW_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 {
+
+// Manages the events that Chrome has selected on X windows which were not
+// created by Chrome. This class allows several clients to select events
+// on the same X window.
+class UI_BASE_X_EXPORT XWindowManager {

[Elliot Glaysher, 2016/09/06 20:11:56]

The name XWindowManager is a bit deceptive for anyone who knows about X.
Something like XwindowSelectionManager? XWindowEventManager?

[Tom (Use chromium acct), 2016/09/06 22:08:29]

Done. Renamed to XWindowEventManager

+ public:
+  static XWindowManager* GetInstance();
+
+  // Guarantees that events on |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);
+
+ private:
+  friend struct base::DefaultSingletonTraits<XWindowManager>;
+
+  struct MultiMask {
+    MultiMask();
+    ~MultiMask();
+
+    void AddMask(uint32_t mask);
+    void RemoveMask(uint32_t mask);
+    uint32_t ToMask() const;
+
+    static constexpr auto kMaskSize = 25;
+
+    unsigned int mask_bits[kMaskSize];
+  };
+
+  XWindowManager();
+  ~XWindowManager();
+
+  void BeforeMaskChanged(XID xid);
+  void AfterMaskChanged(XID xid);
+
+  // State for [Before|After]MaskChanged
+  uint32_t old_mask_;
+
+  std::map<XID, MultiMask> mask_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(XWindowManager);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_X_X11_FOREIGN_WINDOW_MANAGER_H_