Update SVG interfaces to stop inheriting from SVGURIReference

Source/core/core.gypi

 {
     'variables': {
         'core_idl_files': [
             'css/CSS.idl',
             'css/CSSCharsetRule.idl',
             'css/CSSFontFaceLoadEvent.idl',
             'css/CSSFontFaceRule.idl',
             'css/CSSHostRule.idl',
             'css/CSSImportRule.idl',
             'css/CSSMediaRule.idl',
@@ skipping 437 matching lines @@
             'svg/SVGSymbolElement.idl',
             'svg/SVGTRefElement.idl',
             'svg/SVGTSpanElement.idl',
             'svg/SVGTextContentElement.idl',
             'svg/SVGTextElement.idl',
             'svg/SVGTextPathElement.idl',
             'svg/SVGTextPositioningElement.idl',
             'svg/SVGTitleElement.idl',
             'svg/SVGTransform.idl',
             'svg/SVGTransformList.idl',
+            'svg/SVGURIReference.idl',
             'svg/SVGUnitTypes.idl',
             'svg/SVGUseElement.idl',
             'svg/SVGViewElement.idl',
             'svg/SVGViewSpec.idl',
             'svg/SVGVKernElement.idl',
             'svg/SVGZoomAndPan.idl',
             'svg/SVGZoomEvent.idl',
         ],
         'webcore_files': [
             'Init.cpp',
@@ skipping 3221 matching lines @@
                 'bison_exe': 'bison',
                 # We specify a preprocess so it happens locally and won't get
                 # distributed to goma.
                 # FIXME: /usr/bin/gcc won't exist on OSX forever. We want to
                 # use /usr/bin/clang once we require Xcode 4.x.
                 'preprocessor': '--preprocessor "/usr/bin/gcc -E -P -x c++"'
               }],
          ],
     }
 }