[SVGDom] Add <circle>, <ellipse> support

experimental/svg/model/SkSVGNode.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkSVGNode_DEFINED
 #define SkSVGNode_DEFINED
 
 #include "SkRefCnt.h"
 #include "SkSVGAttribute.h"
 
 class SkCanvas;
 class SkMatrix;
 class SkSVGRenderContext;
 class SkSVGValue;
 
 enum class SkSVGTag {
+    kCircle,
+    kEllipse,
     kG,
     kPath,
     kPolygon,
     kPolyline,
     kRect,
     kSvg
 };
 
 class SkSVGNode : public SkRefCnt {
 public:
@@ skipping 32 matching lines @@
 private:
     SkSVGTag                    fTag;
 
     // FIXME: this should be sparse
     SkSVGPresentationAttributes fPresentationAttributes;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif // SkSVGNode_DEFINED