Accelerated filters should filter unpadded primitives.

third_party/WebKit/Source/core/paint/PaintLayer.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
index df982ee3b772a6d2fc8da5b4bab1e45cf1824700..f1f683b47c1d4b69f10391d4f6de1780a9c81348 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -2243,10 +2243,11 @@ LayoutRect PaintLayer::boundingBoxForCompositing(const PaintLayer* ancestorLayer
         else
             expandRectForReflectionAndStackingChildren(this, result);
 
-        // FIXME: We can optimize the size of the composited layers, by not enlarging
-        // filtered areas with the outsets if we know that the filter is going to render in hardware.
-        // https://bugs.webkit.org/show_bug.cgi?id=81239
-        result.expand(filterOutsets());
+        // Only enlarge by the filter outsets if we know the filter is going to be rendered in software.
+        // Accelerated filters will handle their own outsets.
+        if (paintsWithFilters()) {
+            result.expand(filterOutsets());
+        }
     }
 
     if (transform() && paintsWithTransform(GlobalPaintNormalPhase) && (this != ancestorLayer || options == MaybeIncludeTransformForAncestorLayer))