Eliminate copies of encoded image data

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

Index: third_party/WebKit/Source/platform/graphics/PictureSnapshot.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/PictureSnapshot.cpp b/third_party/WebKit/Source/platform/graphics/PictureSnapshot.cpp
index 2746fbf217dcf0933e2abbe00ccbf2fbd48a1e52..3c8e3365bec5af33142fa266cf255c95cb9d8484 100644
--- a/third_party/WebKit/Source/platform/graphics/PictureSnapshot.cpp
+++ b/third_party/WebKit/Source/platform/graphics/PictureSnapshot.cpp
@@ -36,9 +36,11 @@
 #include "platform/graphics/ProfilingCanvas.h"
 #include "platform/graphics/ReplayingCanvas.h"
 #include "platform/graphics/skia/ImagePixelLocker.h"
+#include "platform/image-decoders/DataSegmentReader.h"
 #include "platform/image-decoders/ImageDecoder.h"
 #include "platform/image-decoders/ImageFrame.h"
 #include "platform/image-encoders/skia/PNGImageEncoder.h"
+#include "third_party/skia/include/core/SkData.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkPictureRecorder.h"
 #include "third_party/skia/include/core/SkStream.h"
@@ -55,11 +57,14 @@ PictureSnapshot::PictureSnapshot(PassRefPtr<const SkPicture> picture)
 
 static bool decodeBitmap(const void* data, size_t length, SkBitmap* result)
 {
-    RefPtr<SharedBuffer> buffer = SharedBuffer::create(static_cast<const char*>(data), length);
-    OwnPtr<ImageDecoder> imageDecoder = ImageDecoder::create(*buffer, ImageDecoder::AlphaPremultiplied, ImageDecoder::GammaAndColorProfileIgnored);
+    OwnPtr<ImageDecoder> imageDecoder = ImageDecoder::create(static_cast<const char*>(data), length,
+        ImageDecoder::AlphaPremultiplied, ImageDecoder::GammaAndColorProfileIgnored);
     if (!imageDecoder)
         return false;
-    imageDecoder->setData(buffer.get(), true);
+
+    // No need to copy the data; this decodes immediately.
+    RefPtr<DataSegmentReader> segmentReader = new DataSegmentReader(adoptRef(SkData::NewWithoutCopy(data, length)));

[scroggo_chromium, 2016/03/24 13:59:46]

Oops, I think the DataSegmentReader needs to be adopted. Fixed in next patch
set.

+    imageDecoder->setData(segmentReader.release(), true);
     ImageFrame* frame = imageDecoder->frameBufferAtIndex(0);
     if (!frame)
         return true;