Harmonize FilterEffect::mapRect and mapPaintRect

third_party/WebKit/LayoutTests/paint/invalidation/filters/effect-reference-repaint-gaussianblur-expected.txt

Index: third_party/WebKit/LayoutTests/paint/invalidation/filters/effect-reference-repaint-gaussianblur-expected.txt
diff --git a/third_party/WebKit/LayoutTests/paint/invalidation/filters/effect-reference-repaint-gaussianblur-expected.txt b/third_party/WebKit/LayoutTests/paint/invalidation/filters/effect-reference-repaint-gaussianblur-expected.txt
index 8954704801f73d8d36f2d1dad6ea7928916cfbc8..dbba95ce8b3a27a91fa78af9cbb2d8bc98c12f31 100644
--- a/third_party/WebKit/LayoutTests/paint/invalidation/filters/effect-reference-repaint-gaussianblur-expected.txt
+++ b/third_party/WebKit/LayoutTests/paint/invalidation/filters/effect-reference-repaint-gaussianblur-expected.txt
@@ -10,7 +10,7 @@
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow DIV class='box'",
-          "rect": [1, -7, 314, 314],
+          "rect": [38, 30, 240, 240],

[Stephen White, 2016/09/20 15:36:19]

OK, so thanks to your change, this is now more precise, since we're invalidating
only the filter region in this case (-10%, -10%, 120%, 120%). But the test is
less useful, since it doesn't really exercise what it was designed to, which is
FEGaussianBlur::mapRect() (now mapEffect()).

Could you modify the test so the <filter> primitive has something super-large,
like x=-50%, y=-50%, width=200%, height=200%? Then we should see the actual blur
radius show up here, approx. -60, -60, 320 x 320.

We should probably do the same for all filter-effect-repaint-* tests.

(This is probably my fault, since I implemented filter subregion correctly for
CSS filters, these tests are clipping to the filter region where they weren't
before, but were still using an unclipped paint invalidation region.)

[fs, 2016/09/20 19:14:14]

Changed per suggestion above.

           "reason": "style change"
         }
       ]