Specify the source rect on the SourceGraphic

Source/platform/graphics/filters/SourceGraphic.cpp

Index: Source/platform/graphics/filters/SourceGraphic.cpp
diff --git a/Source/platform/graphics/filters/SourceGraphic.cpp b/Source/platform/graphics/filters/SourceGraphic.cpp
index 12aa4bd79848436aef336fc1118b70250cb904a2..7a71d90a850006ccea21edd3cc3ddec62ea2ca48 100644
--- a/Source/platform/graphics/filters/SourceGraphic.cpp
+++ b/Source/platform/graphics/filters/SourceGraphic.cpp
@@ -52,8 +52,7 @@ const AtomicString& SourceGraphic::effectName()
 
 FloatRect SourceGraphic::determineAbsolutePaintRect(const FloatRect& requestedRect)
 {
-    FloatRect srcRect = filter()->sourceImageRect();
-    srcRect.intersect(requestedRect);
+    FloatRect srcRect = intersection(m_sourceRect, requestedRect);
     addAbsolutePaintRect(srcRect);
     return srcRect;
 }
@@ -63,6 +62,11 @@ void SourceGraphic::setPicture(PassRefPtr<const SkPicture> picture)
     m_picture = picture;
 }
 
+void SourceGraphic::setSourceRect(const IntRect& sourceRect)
+{
+    m_sourceRect = sourceRect;
+}
+
 PassRefPtr<SkImageFilter> SourceGraphic::createImageFilter(SkiaImageFilterBuilder*)
 {
     if (!m_picture)