Add window manager component.

wm/host/foreign_window_host_delegate.h

+// Copyright (c) 2013 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 WM_HOST_FOREIGN_WINDOW_HOST_DELEGATE_H_
+#define WM_HOST_FOREIGN_WINDOW_HOST_DELEGATE_H_
+
+namespace wm {
+
+// A private interface used by ForeignWindowHost implementations to communicate
+// with their owning ForeignWindow.
+class ForeignWindowHostDelegate {
+ public:
+  virtual void OnWindowContentsChanged() = 0;
+
+ protected:
+  virtual ~ForeignWindowHostDelegate() {}
+};
+
+}  // namespace wm
+
+#endif  // WM_HOST_FOREIGN_WINDOW_HOST_DELEGATE_H_