Implement image-rendering:pixelated for directly composited images.

Source/core/rendering/compositing/CompositedLayerMapping.cpp

Index: Source/core/rendering/compositing/CompositedLayerMapping.cpp
diff --git a/Source/core/rendering/compositing/CompositedLayerMapping.cpp b/Source/core/rendering/compositing/CompositedLayerMapping.cpp
index cc99507e1de68605435e5354a08e4b47b46d917b..143314471c68cc4a5bb08db571fa9608b2f04084 100644
--- a/Source/core/rendering/compositing/CompositedLayerMapping.cpp
+++ b/Source/core/rendering/compositing/CompositedLayerMapping.cpp
@@ -1864,6 +1864,8 @@ void CompositedLayerMapping::updateImageContents()
     // This is a no-op if the layer doesn't have an inner layer for the image.
     m_graphicsLayer->setContentsToImage(image);
 
+    m_graphicsLayer->setFilterLevel(renderer()->style()->imageRendering() == ImageRenderingPixelated ? SkPaint::kNone_FilterLevel : SkPaint::kLow_FilterLevel);
+
     // Prevent double-drawing: https://bugs.webkit.org/show_bug.cgi?id=58632
     updateDrawsContent();