Fixing performance issue of creating imagebitmap from ImageData

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

 /*
  * Copyright (c) 2013, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 20 matching lines @@
 #include "config.h"
 #include "platform/graphics/UnacceleratedImageBufferSurface.h"
 
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkDevice.h"
 #include "third_party/skia/include/core/SkSurface.h"
 #include "wtf/PassRefPtr.h"
 
 namespace blink {
 
-UnacceleratedImageBufferSurface::UnacceleratedImageBufferSurface(const IntSize& size, OpacityMode opacityMode)
+UnacceleratedImageBufferSurface::UnacceleratedImageBufferSurface(const IntSize& size, OpacityMode opacityMode, ImageInitializationMode initializationMode)
     : ImageBufferSurface(size, opacityMode)
 {
     SkAlphaType alphaType = (Opaque == opacityMode) ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
     SkImageInfo info = SkImageInfo::MakeN32(size.width(), size.height(), alphaType);
     SkSurfaceProps disableLCDProps(0, kUnknown_SkPixelGeometry);
     m_surface = adoptRef(SkSurface::NewRaster(info, Opaque == opacityMode ? 0 : &disableLCDProps));
 
-    if (m_surface)
-        clear();
+    if (initializationMode == DoNotInitializeImagePixels) {

[rickyz (no longer on Chrome), 2016/01/19 23:34:49]

Is this logic correct? Shouldn't this clear initializationMode ==
InitializeImagePixels?

On the other hand, ClusterFuzz said that this CL fixed the issue, so maybe I'm
just seeing things?

[rickyz (no longer on Chrome), 2016/01/19 23:43:10]

Never mind, I see that this was fixed in a later CL
(https://codereview.chromium.org/1407393002).

+        if (m_surface)
+            clear();
+    }
 }
 
 UnacceleratedImageBufferSurface::~UnacceleratedImageBufferSurface() { }
 
 SkCanvas* UnacceleratedImageBufferSurface::canvas()
 {
     return m_surface->getCanvas();
 }
 
 const SkBitmap& UnacceleratedImageBufferSurface::deprecatedBitmapForOverwrite()
 {
     m_surface->notifyContentWillChange(SkSurface::kDiscard_ContentChangeMode);
     return m_surface->getCanvas()->getDevice()->accessBitmap(false);
 }
 
 bool UnacceleratedImageBufferSurface::isValid() const
 {
     return m_surface;
 }
 
 PassRefPtr<SkImage> UnacceleratedImageBufferSurface::newImageSnapshot(AccelerationHint)
 {
     return adoptRef(m_surface->newImageSnapshot());
 }
 
 } // namespace blink