remove a few static initializers

ui/views/animation/ink_drop_animation_observer.h

 // Copyright 2015 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_ANIMATION_INK_DROP_ANIMATION_OBSERVER_H_
 #define UI_VIEWS_ANIMATION_INK_DROP_ANIMATION_OBSERVER_H_
 
-#include <iosfwd>
 #include <string>
 
 #include "base/macros.h"
 #include "ui/views/animation/ink_drop_state.h"
 #include "ui/views/views_export.h"
 
 namespace views {
 
 // Pure-virtual base class of an observer that can be attached to
 // InkDropAnimations.
@@ skipping 29 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(InkDropAnimationObserver);
 };
 
 // Returns a human readable string for |reason|.  Useful for logging.
 std::string ToString(
     InkDropAnimationObserver::InkDropAnimationEndedReason reason);
 
 }  // namespace views
 
 #endif  // UI_VIEWS_ANIMATION_INK_DROP_ANIMATION_OBSERVER_H_