Pass preallocation hints to SkRWBuffer

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

Index: third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp b/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp
index ca65e9ced4dec0d05229fd3a47a0b151099289dc..44cc03621918fb73eed6523738d644b51dcc6e9a 100644
--- a/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp
+++ b/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp
@@ -165,7 +165,9 @@ void DeferredImageDecoder::setDataInternal(PassRefPtr<SharedBuffer> passData,
     const char* segment = 0;
     for (size_t length = data->getSomeData(segment, m_rwBuffer->size()); length;
          length = data->getSomeData(segment, m_rwBuffer->size())) {
-      m_rwBuffer->append(segment, length);
+      DCHECK_GE(data->size(), m_rwBuffer->size() + length);
+      const size_t remaining = data->size() - m_rwBuffer->size() - length;
+      m_rwBuffer->append(segment, length, remaining);
     }
   }
 }