Don't include ComputedStyle.h where not needed.

third_party/WebKit/Source/core/style/ShadowList.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef ShadowList_h
 #define ShadowList_h
 
-#include "core/style/ComputedStyle.h"
 #include "core/style/ShadowData.h"
 #include "platform/geometry/FloatRectOutsets.h"
 #include "platform/geometry/LayoutRect.h"
 #include "platform/graphics/DrawLooperBuilder.h"
 #include "wtf/RefCounted.h"
 #include "wtf/Vector.h"
 #include <memory>
 
 namespace blink {
 
@@ skipping 37 matching lines @@
     ASSERT(!shadows.isEmpty());
     m_shadows.swap(shadows);
     m_shadows.shrinkToFit();
   }
   ShadowDataVector m_shadows;
 };
 
 }  // namespace blink
 
 #endif  // ShadowList_h