[SVGDom] Opacity optimization

experimental/svg/model/SkSVGNode.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 "SkMatrix.h"
 #include "SkSVGNode.h"
@@ skipping 13 matching lines @@
     }
 }
 
 bool SkSVGNode::asPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const {
     SkSVGRenderContext localContext(ctx);
 
     return this->onPrepareToRender(&localContext) && this->onAsPaint(localContext, paint);
 }
 
 bool SkSVGNode::onPrepareToRender(SkSVGRenderContext* ctx) const {
-    ctx->applyPresentationAttributes(fPresentationAttributes);
+    ctx->applyPresentationAttributes(fPresentationAttributes,
+                                     this->hasChildren() ? 0 : SkSVGRenderContext::kLeaf);
     return true;
 }
 
 void SkSVGNode::setAttribute(SkSVGAttribute attr, const SkSVGValue& v) {
     this->onSetAttribute(attr, v);
 }
 
 void SkSVGNode::setFill(const SkSVGPaint& svgPaint) {
     fPresentationAttributes.fFill.set(svgPaint);
 }
@@ skipping 61 matching lines @@
     case SkSVGAttribute::kStrokeWidth:
         if (const SkSVGLengthValue* strokeWidth = v.as<SkSVGLengthValue>()) {
             this->setStrokeWidth(*strokeWidth);
         }
         break;
     default:
         SkDebugf("attribute ID <%d> ignored for node <%d>\n", attr, fTag);
         break;
     }
 }