Implement image-rendering:pixelated for accelerated 2D canvases.

Source/core/html/HTMLCanvasElement.cpp

Index: Source/core/html/HTMLCanvasElement.cpp
diff --git a/Source/core/html/HTMLCanvasElement.cpp b/Source/core/html/HTMLCanvasElement.cpp
index 08bbb9b8ed8e510a2487914d4857ad8a741af137..ceb28f5de7582efd2e1d8518846ca0cfb6ba4079 100644
--- a/Source/core/html/HTMLCanvasElement.cpp
+++ b/Source/core/html/HTMLCanvasElement.cpp
@@ -149,9 +149,11 @@ RenderObject* HTMLCanvasElement::createRenderer(RenderStyle* style)
 void HTMLCanvasElement::didRecalcStyle(StyleRecalcChange)
 {
     SkPaint::FilterLevel filterLevel = computedStyle()->imageRendering() == ImageRenderingPixelated ? SkPaint::kNone_FilterLevel : SkPaint::kLow_FilterLevel;
-    if (m_context && m_context->is3d()) {
+    if (is3D()) {
         toWebGLRenderingContext(m_context.get())->setFilterLevel(filterLevel);
         setNeedsCompositingUpdate();
+    } else if (hasImageBuffer()) {
+        m_imageBuffer->setFilterLevel(filterLevel);
     }
 }
 
@@ -627,6 +629,10 @@ void HTMLCanvasElement::createImageBufferInternal()
     m_imageBuffer = ImageBuffer::create(surface.release());
     m_imageBuffer->setClient(this);
 
+    document().updateRenderTreeIfNeeded();
+    RenderStyle* style = computedStyle();
+    m_imageBuffer->setFilterLevel((style && (style->imageRendering() == ImageRenderingPixelated)) ? SkPaint::kNone_FilterLevel : SkPaint::kLow_FilterLevel);
+
     m_didFailToCreateImageBuffer = false;
 
     updateExternallyAllocatedMemory();
@@ -813,6 +819,8 @@ PassRefPtr<Image> HTMLCanvasElement::getSourceImageForCanvas(SourceImageMode mod
         return createTransparentImage(size());
     }
 
+    m_imageBuffer->willAccessPixels();
+
     if (m_context->is3d()) {
         m_context->paintRenderingResultsToCanvas(BackBuffer);
         *status = ExternalSourceImageStatus;