Modifications to DisplayList for better Slimming Paint

Source/core/svg/graphics/filters/SVGFEImage.cpp

Index: Source/core/svg/graphics/filters/SVGFEImage.cpp
diff --git a/Source/core/svg/graphics/filters/SVGFEImage.cpp b/Source/core/svg/graphics/filters/SVGFEImage.cpp
index de94de80f00eacb415afd011cd40f224141faabd..d4e573d341d500a58bd352bb13f7e7b6c2bda2ba 100644
--- a/Source/core/svg/graphics/filters/SVGFEImage.cpp
+++ b/Source/core/svg/graphics/filters/SVGFEImage.cpp
@@ -72,6 +72,14 @@ static FloatRect getRendererRepaintRect(RenderObject* renderer)
         renderer->paintInvalidationRectInLocalCoordinates());
 }
 
+AffineTransform makeMapBetweenRects(const FloatRect& source, const FloatRect& dest)

[chrishtr, 2014/09/02 22:05:58]

Is this function called anywhere?

[Stephen Chennney, 2014/09/03 14:19:37]

Yep, 3 times in this file only. I wanted to replace it with the corresponding
SkMatrix method it because it does not really do what the name implies, but it
turns out it's hard to replicate due to some stupidity in
AffineTransform::scale. So I moved it here to prevent other code from pulling it
in.

+{
+    AffineTransform transform;
+    transform.translate(dest.x() - source.x(), dest.y() - source.y());
+    transform.scale(dest.width() / source.width(), dest.height() / source.height());
+    return transform;
+}
+
 FloatRect FEImage::determineAbsolutePaintRect(const FloatRect& originalRequestedRect)
 {
     RenderObject* renderer = referencedRenderer();
@@ -203,11 +211,13 @@ PassRefPtr<SkImageFilter> FEImage::createImageFilterForRenderer(RenderObject* re
     if (!context)
         return adoptRef(SkBitmapSource::Create(SkBitmap()));
     AffineTransform contentTransformation;
+    FloatRect bounds(FloatPoint(), dstRect.size());
+    RefPtr<DisplayList> displayList = DisplayList::create(bounds);
     context->save();
-    context->beginRecording(FloatRect(FloatPoint(), dstRect.size()));
+    context->beginRecording(displayList);
     context->concatCTM(transform);
     SVGRenderingContext::renderSubtree(context, renderer, contentTransformation);
-    RefPtr<DisplayList> displayList = context->endRecording();
+    context->endRecording();
     context->restore();
     RefPtr<SkImageFilter> result = adoptRef(SkPictureImageFilter::Create(displayList->picture(), dstRect));
     return result.release();