Make a pure mojo::View version of the aura::Window FocusController.

mojo/services/public/cpp/view_manager/view_tracker.h

Index: mojo/services/public/cpp/view_manager/view_tracker.h
diff --git a/mojo/services/public/cpp/view_manager/view_tracker.h b/mojo/services/public/cpp/view_manager/view_tracker.h
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index 0000000000000000000000000000000000000000..c11f6f8fe8d735fb63cc11370048e4ec48bb4296
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+++ b/mojo/services/public/cpp/view_manager/view_tracker.h
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+// 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 MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_TRACKER_H_
+#define MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_TRACKER_H_
+
+#include <set>
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "mojo/services/public/cpp/view_manager/view_observer.h"
+
+namespace mojo {
+
+class ViewTracker : public ViewObserver {
+ public:
+  typedef std::set<View*> Views;

[sky, 2014/11/10 20:45:30]

using Views = std::set<View*>

+
+  ViewTracker();
+  ~ViewTracker() override;
+
+  // Returns the set of views being observed.
+  const std::set<View*>& views() const { return views_; }
+
+  // Adds |view| to the set of Views being tracked.
+  void Add(View* view);
+
+  // Removes |view| from the set of views being tracked.
+  void Remove(View* view);
+
+  // Returns true if |view| was previously added and has not been removed or
+  // deleted.
+  bool Contains(View* view);
+
+  // ViewObserver overrides:
+  virtual void OnViewDestroying(View* view) override;
+
+ private:
+  Views views_;
+
+  DISALLOW_COPY_AND_ASSIGN(ViewTracker);
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_TRACKER_H_