[SVGDom] Expose intrinsic size info

experimental/svg/model/SkSVGSVG.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkSVGRenderContext.h"
 #include "SkSVGSVG.h"
@@ skipping 77 matching lines @@
         break;
     case SkSVGAttribute::kViewBox:
         if (const auto* vb = v.as<SkSVGViewBoxValue>()) {
             this->setViewBox(*vb);
         }
         break;
     default:
         this->INHERITED::onSetAttribute(attr, v);
     }
 }
+
+// https://www.w3.org/TR/SVG/coords.html#IntrinsicSizing
+SkSize SkSVGSVG::intrinsicSize(const SkSVGLengthContext& lctx) const {
+    // Percentage values do not provide an intrinsic size.
+    if (fWidth.unit() == SkSVGLength::Unit::kPercentage ||
+        fHeight.unit() == SkSVGLength::Unit::kPercentage) {
+        return SkSize::Make(0, 0);
+    }
+
+    return SkSize::Make(lctx.resolve(fWidth, SkSVGLengthContext::LengthType::kHorizontal),
+                        lctx.resolve(fHeight, SkSVGLengthContext::LengthType::kVertical));
+}