Copy SharedBuffer before calling decodeImageData

Source/web/ImageDecodeBench.cpp

Index: Source/web/ImageDecodeBench.cpp
diff --git a/Source/web/ImageDecodeBench.cpp b/Source/web/ImageDecodeBench.cpp
index 2f6f2b47c90d68347c208ef1f0e10f18f6444e69..6067ab92d4bb7af5529b8f38ed176585be93807b 100644
--- a/Source/web/ImageDecodeBench.cpp
+++ b/Source/web/ImageDecodeBench.cpp
@@ -365,8 +365,14 @@ int main(int argc, char* argv[])
     double totalTime = 0.0;
 
     for (size_t i = 0; i < iterations; ++i) {
+        // Copy the SharedBuffer. Note that we do not want to call
+        // SharedBuffer::copy, which would merge all the segments. We want this
+        // to look just like it would receiving partial data off the web.
+        // After this call, data will have its segments merged, but not tempData.
+        RefPtr<SharedBuffer> tempData = SharedBuffer::create(data->data(), data->size());
+
         double startTime = getCurrentTime();
-        bool decoded = decodeImageData(data.get(), applyColorCorrection);
+        bool decoded = decodeImageData(tempData.get(), applyColorCorrection);
         double elapsedTime = getCurrentTime() - startTime;
         totalTime += elapsedTime;
         if (!decoded) {