Ganesh: images upload to GPU performance fix (skip copying encoded data)

third_party/WebKit/Source/platform/graphics/ThreadSafeDataTransport.cpp

 /*
  * Copyright (C) 2012 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 36 matching lines @@
     ASSERT(buffer->size() >= m_readPosition);
     Vector<RefPtr<SharedBuffer>> newBufferQueue;
 
     const char* segment = 0;
     while (size_t length = buffer->getSomeData(segment, m_readPosition)) {
         m_readPosition += length;
         newBufferQueue.append(SharedBuffer::create(segment, length));
     }
 
     MutexLocker locker(m_mutex);
+
+    // If all data was previously received, don't append more to it.
+    RELEASE_ASSERT(!(m_allDataReceived && newBufferQueue.size()));
+
     m_newBufferQueue.appendVector(newBufferQueue);
     newBufferQueue.clear();
     m_allDataReceived = allDataReceived;
 }
 
 void ThreadSafeDataTransport::data(SharedBuffer** buffer, bool* allDataReceived)
 {
     ASSERT(buffer);
     ASSERT(allDataReceived);
     Vector<RefPtr<SharedBuffer>> newBufferQueue;
     {
         MutexLocker lock(m_mutex);
         m_newBufferQueue.swap(newBufferQueue);
         *allDataReceived = m_allDataReceived;
     }
     for (size_t i = 0; i < newBufferQueue.size(); ++i)
         m_readBuffer->append(newBufferQueue[i].get());
     *buffer = m_readBuffer.get();
 }
 
 bool ThreadSafeDataTransport::hasNewData()
 {
     MutexLocker lock(m_mutex);
     return !m_newBufferQueue.isEmpty();
 }
 
 } // namespace blink