Eliminate copies of encoded image data

third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp

Index: third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp
diff --git a/third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp b/third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp
index 2672862d85e13b5b65612075ffccf1ef424f6463..0b8ef11a035a640d9c32083bea64c5b94eff97d9 100644
--- a/third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp
+++ b/third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp
@@ -155,7 +155,7 @@ void WEBPImageDecoder::clearDecoder()
     m_frameBackgroundHasAlpha = false;
 }
 
-void WEBPImageDecoder::onSetData(SharedBuffer*)
+void WEBPImageDecoder::onSetData(SegmentReader*)
 {
     m_haveAlreadyParsedThisData = false;
 }
@@ -195,7 +195,8 @@ bool WEBPImageDecoder::updateDemuxer()
         return false; // Await VP8X header so WebPDemuxPartial succeeds.
 
     WebPDemuxDelete(m_demux);
-    WebPData inputData = { reinterpret_cast<const uint8_t*>(m_data->data()), m_data->size() };
+    m_encodedData = m_data->getAsSkData();

[Peter Kasting, 2016/03/25 06:24:37]

We never reset this anywhere; won't this mean we now hang onto the last data we
looked at even after decoding has finished (succeeded or failed)?

[scroggo, 2016/03/25 15:49:53]

That looks correct. I've updated the code to clear m_encodedData any time we
clear m_demux. Will add urvang@ to look over changes here.

+    WebPData inputData = { reinterpret_cast<const uint8_t*>(m_encodedData->data()), m_encodedData->size() };
     m_demux = WebPDemuxPartial(&inputData, &m_demuxState);
     if (!m_demux || (isAllDataReceived() && m_demuxState != WEBP_DEMUX_DONE))
         return setFailed();