Rewrite references to "wtf/" to "platform/wtf/" in core/animation.

third_party/WebKit/Source/core/animation/DocumentAnimation.h

 // 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 DocumentAnimation_h
 #define DocumentAnimation_h
 
 #include "core/dom/Document.h"
-#include "wtf/Allocator.h"
+#include "platform/wtf/Allocator.h"
 
 namespace blink {
 
 class DocumentAnimation {
   STATIC_ONLY(DocumentAnimation);
 
  public:
   static DocumentTimeline* timeline(Document& document) {
     return &document.timeline();
   }
 };
 
 }  // namespace blink
 
 #endif  // DocumentAnimation_h