Check SkStream::isAtEnd before attempting to read.

src/utils/SkFrontBufferedStream.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkFrontBufferedStream.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
@@ skipping 157 matching lines @@
         // and the destination buffer.
         size -= bytesCopied;
         SkASSERT(size + (fOffset - start) == totalSize);
         if (dst != NULL) {
             dst += bytesCopied;
         }
     }
 
     // Buffer any more data that should be buffered, and copy it to the
     // destination.
-    if (size > 0 && fBufferedSoFar < fBufferSize) {
+    if (size > 0 && fBufferedSoFar < fBufferSize && !fStream->isAtEnd()) {
         const size_t buffered = this->bufferAndWriteTo(dst, size);
 
         // Update the remaining number of bytes needed to read
         // and the destination buffer.
         size -= buffered;
         SkASSERT(size + (fOffset - start) == totalSize);
         if (dst != NULL) {
             dst += buffered;
         }
     }
 
     if (size > 0 && !fStream->isAtEnd()) {
         SkDEBUGCODE(const size_t bytesReadDirectly =) this->readDirectlyFromStream(dst, size);
         SkDEBUGCODE(size -= bytesReadDirectly;)
         SkASSERT(size + (fOffset - start) == totalSize);
     }
 
     return fOffset - start;
 }