Merge 131315 - Calling WebCore::SharedBuffer::append(data, 0) on a shared buffer when

Source/WebCore/platform/SharedBuffer.cpp

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 129 matching lines @@
     size_t position = 0;
     while (size_t length = data->getSomeData(segment, position)) {
         append(segment, length);
         position += length;
     }
 }
 
 void SharedBuffer::append(const char* data, unsigned length)
 {
     ASSERT(!m_purgeableBuffer);
+    if (!length)
+        return;
 
     maybeTransferPlatformData();
     
     unsigned positionInSegment = offsetInSegment(m_size - m_buffer.size());
     m_size += length;
 
     if (m_size <= segmentSize) {
         // No need to use segments for small resource data
         m_buffer.append(data, length);
         return;
@@ skipping 183 matching lines @@
     const UChar* d = string.characters();
     WTF::Unicode::ConversionResult result = WTF::Unicode::convertUTF16ToUTF8(&d, d + length, &p, p + buffer.size(), true);
     if (result != WTF::Unicode::conversionOK)
         return 0;
 
     buffer.shrink(p - buffer.data());
     return SharedBuffer::adoptVector(buffer);
 }
 
 } // namespace WebCore