Remove support for the externalResourcesRequired attribute.

LayoutTests/svg/W3C-SVG-1.1-SE/types-dom-04-b-expected.txt

Index: LayoutTests/svg/W3C-SVG-1.1-SE/types-dom-04-b-expected.txt
diff --git a/LayoutTests/svg/W3C-SVG-1.1-SE/types-dom-04-b-expected.txt b/LayoutTests/svg/W3C-SVG-1.1-SE/types-dom-04-b-expected.txt
index c5f8dda395e3275e2630d7fa3196b122180f2264..ac6efb406f721a822a6177889cc0357ab22fe97f 100644
--- a/LayoutTests/svg/W3C-SVG-1.1-SE/types-dom-04-b-expected.txt
+++ b/LayoutTests/svg/W3C-SVG-1.1-SE/types-dom-04-b-expected.txt
@@ -136,7 +136,8 @@ layer at (0,0) size 480x360
         RenderSVGResourceMarker {marker} [id="marker"] [markerUnits=strokeWidth] [ref at (0,0)] [angle=60.00]
         RenderSVGViewportContainer {svg} at (0,0) size 0x0
         RenderSVGResourceFilter {filter} [id=""] [filterUnits=objectBoundingBox] [primitiveUnits=userSpaceOnUse]
-          [feTurbulence type="TURBULENCE" baseFrequency="4.00, 5.00" seed="0.00" numOctaves="1" stitchTiles="0"]
+          [feConvolveMatrix order="width=3 height=3" kernelMatrix="[1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00]" divisor="9.00" bias="0.00" target="(1,1)" edgeMode="DUPLICATE" kernelUnitLength="(1,1)" preserveAlpha="1"]
+            [feTurbulence type="TURBULENCE" baseFrequency="4.00, 5.00" seed="0.00" numOctaves="1" stitchTiles="0"]
     RenderSVGContainer {g} at (10,314) size 227x33
       RenderSVGText {text} at (10,314) size 227x33 contains 1 chunk(s)
         RenderSVGInlineText {#text} at (0,0) size 227x32