Fix FEImage SKP bounds

When recording its filterPicture, FEImage::createImageFilterForLayoutObject() transforms the
content such that it draws into dstRect - but it keeps the recording bounds at origin
(FloatRect(FloatPoint(), dstRect.size())).

This means that the picture content can draw outside its declared bounds, and is susceptible to
incorrect culling.

Since we're mapping the content into dstRect, we should use the same for picture culling.

R=senorblanco@chromium.org

Review URL: https://codereview.chromium.org/1298283003

git-svn-id: svn://svn.chromium.org/blink/trunk@200914 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -174,7 +174,7 @@ PassRefPtr<SkImageFilter> FEImage::createImageFilterForLayoutObject(LayoutObject
         transform.translate(dstRect.x(), dstRect.y());
     }
 
-    SkPictureBuilder filterPicture(FloatRect(FloatPoint(), dstRect.size()));
+    SkPictureBuilder filterPicture(dstRect);
     {
         TransformRecorder transformRecorder(filterPicture.context(), layoutObject, transform);
         SVGPaintContext::paintSubtree(&filterPicture.context(), &layoutObject);