Allow Widget to pass accelerator handling to its parent.

ui/views/widget/widget_accelerator_handling_delegate.h

Index: ui/views/widget/widget_accelerator_handling_delegate.h
diff --git a/ui/views/widget/widget_accelerator_handling_delegate.h b/ui/views/widget/widget_accelerator_handling_delegate.h
new file mode 100644
index 0000000000000000000000000000000000000000..3f9c897f1eaafe73c1a246f651ab903424d021bd
--- /dev/null
+++ b/ui/views/widget/widget_accelerator_handling_delegate.h
@@ -0,0 +1,42 @@
+// Copyright (c) 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_VIEWS_WIDGET_WIDGET_ACCELERATOR_HANDLING_DELEGATE_H_
+#define UI_VIEWS_WIDGET_WIDGET_ACCELERATOR_HANDLING_DELEGATE_H_
+
+#include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
+#include "ui/views/widget/widget_observer.h"
+
+namespace views {
+
+class FocusManagerDelegate;
+
+class WidgetAcceleratorHandlingDelegate : public WidgetObserver {
+ public:
+  explicit WidgetAcceleratorHandlingDelegate(Widget* accelerator_target);
+  ~WidgetAcceleratorHandlingDelegate() override;
+
+  Widget* accelerator_target() const { return accelerator_target_; }
+
+  base::WeakPtr<WidgetAcceleratorHandlingDelegate> GetWeakPtr();
+
+  std::unique_ptr<FocusManagerDelegate> CreateFocusManagerDelegate();
+
+  // Implements WidgetObserver:
+  void OnWidgetDestroying(Widget* widget) override;
+
+ private:
+  Widget* accelerator_target_;
+  ScopedObserver<Widget, WidgetAcceleratorHandlingDelegate>
+      accelerator_target_observer_;
+
+  base::WeakPtrFactory<WidgetAcceleratorHandlingDelegate> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(WidgetAcceleratorHandlingDelegate);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_WIDGET_WIDGET_ACCELERATOR_HANDLING_DELEGATE_H_