WTF/std normalization: replace WTF::Vector::last with ::back

third_party/WebKit/Source/platform/image-decoders/gif/GIFImageReader.h

 /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
  *
  * Software distributed under the License is distributed on an "AS IS" basis,
@@ skipping 292 matching lines @@
   bool decode(size_t frameIndex);
 
   size_t imagesCount() const {
     if (m_frames.isEmpty())
       return 0;
 
     // This avoids counting an empty frame when the file is truncated right
     // after GIFControlExtension but before GIFImageHeader.
     // FIXME: This extra complexity is not necessary and we should just report
     // m_frames.size().
-    return m_frames.last()->isHeaderDefined() ? m_frames.size()
+    return m_frames.back()->isHeaderDefined() ? m_frames.size()
                                               : m_frames.size() - 1;
   }
   int loopCount() const { return m_loopCount; }
 
   const GIFColorMap& globalColorMap() const { return m_globalColorMap; }
 
   const GIFFrameContext* frameContext(size_t index) const {
     return index < m_frames.size() ? m_frames[index].get() : 0;
   }
 
@@ skipping 30 matching lines @@
   int m_loopCount;  // Netscape specific extension block to control the number
                     // of animation loops a GIF renders.
 
   Vector<std::unique_ptr<GIFFrameContext>> m_frames;
 
   RefPtr<blink::SegmentReader> m_data;
   bool m_parseCompleted;
 };
 
 #endif