Fix potential bug in FastSharedBufferReader::getConsecutiveData

Source/platform/image-decoders/FastSharedBufferReader.h

 /*
  * Copyright (C) 2015 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 52 matching lines @@
     {
         return *getConsecutiveData(dataPosition, 1, 0);
     }
 
     size_t size() const
     {
         return m_data->size();
     }
 
 private:
+    void getSomeDataIntoCache(unsigned dataPosition);
+
     RefPtr<SharedBuffer> m_data;
 
-    // Caches the last segment of |m_data| accessed, since subsequent reads are
-    // likely to re-access it.
-    const char* m_segment;
-    size_t m_segmentLength;
+    struct Cache {

[Peter Kasting, 2015/03/25 19:53:11]

I don't see what adding this struct buys other than more verbosity.

+        Cache();
 
-    // Data position in |m_data| pointed by |m_segment|.
-    size_t m_dataPosition;
+        // Caches the last segment of |m_data| accessed, since subsequent reads are
+        // likely to re-access it.
+        const char* segment;
+        size_t segmentLength;
+
+        // Data position in |m_data| pointed by |segment|.
+        size_t dataPosition;
+    } m_cache;
 };
 
 } // namespace blink
 
 #endif