Return reference from styleEngine() accessor.

Source/core/page/InjectedStyleSheets.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright 2014 The Chromium Authors. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 37 matching lines @@
     invalidateInjectedStyleSheetCacheInAllFrames();
 }
 
 void InjectedStyleSheets::invalidateInjectedStyleSheetCacheInAllFrames()
 {
     // Clear our cached sheets and have them just reparse.
     const HashSet<Page*>& pages = Page::ordinaryPages();
     for (const Page* page : pages) {
         for (Frame* frame = page->mainFrame(); frame; frame = frame->tree().traverseNext()) {
             if (frame->isLocalFrame())
-                toLocalFrame(frame)->document()->styleEngine()->invalidateInjectedStyleSheetCache();
+                toLocalFrame(frame)->document()->styleEngine().invalidateInjectedStyleSheetCache();
         }
     }
 }
 
 } // namespace blink