Use a composed tree based traversal in computing quads in LinkHighlight::computeQuads().

Source/web/LinkHighlight.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #include "web/LinkHighlight.h"
 
 #include "SkMatrix44.h"
 #include "core/dom/Node.h"
+#include "core/dom/NodeRenderingTraversal.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderLayerModelObject.h"
 #include "core/rendering/RenderObject.h"
 #include "core/rendering/RenderPart.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/compositing/CompositedLayerMapping.h"
 #include "core/rendering/style/ShadowData.h"
 #include "platform/graphics/Color.h"
@@ skipping 131 matching lines @@
 static void addQuadToPath(const FloatQuad& quad, Path& path)
 {
     // FIXME: Make this create rounded quad-paths, just like the axis-aligned case.
     path.moveTo(quad.p1());
     path.addLineTo(quad.p2());
     path.addLineTo(quad.p3());
     path.addLineTo(quad.p4());
     path.closeSubpath();
 }
 
-void LinkHighlight::computeQuads(RenderObject& renderer, Vector<FloatQuad>& outQuads) const
+void LinkHighlight::computeQuads(const Node& node, Vector<FloatQuad>& outQuads) const
 {
+    if (!node.renderer())
+        return;
+
+    RenderObject* renderer = node.renderer();
+
     // For inline elements, absoluteQuads will return a line box based on the line-height
     // and font metrics, which is technically incorrect as replaced elements like images
     // should use their intristic height and expand the linebox  as needed. To get an
     // appropriately sized highlight we descend into the children and have them add their
     // boxes.
-    if (renderer.isRenderInline()) {
-        for (RenderObject* child = renderer.slowFirstChild(); child; child = child->nextSibling())
+    if (renderer->isRenderInline()) {
+        for (Node* child = NodeRenderingTraversal::firstChild(&node); child; child = NodeRenderingTraversal::nextSibling(child))
             computeQuads(*child, outQuads);
     } else {
-        renderer.absoluteQuads(outQuads);
+        renderer->absoluteQuads(outQuads);
     }
 }
 
 bool LinkHighlight::computeHighlightLayerPathAndPosition(RenderLayer* compositingLayer)
 {
     if (!m_node || !m_node->renderer() || !m_currentGraphicsLayer)
         return false;
 
     ASSERT(compositingLayer);
 
     // Get quads for node in absolute coordinates.
     Vector<FloatQuad> quads;
-    computeQuads(*m_node->renderer(), quads);
+    computeQuads(*m_node, quads);
     ASSERT(quads.size());
 
     // Adjust for offset between target graphics layer and the node's renderer.
     FloatPoint positionAdjust = IntPoint(m_currentGraphicsLayer->offsetFromRenderer());
 
     Path newPath;
     for (size_t quadIndex = 0; quadIndex < quads.size(); ++quadIndex) {
         FloatQuad absoluteQuad = quads[quadIndex];
         absoluteQuad.move(-positionAdjust.x(), -positionAdjust.y());
 
@@ skipping 134 matching lines @@
     // Make sure we update geometry on the next callback from WebViewImpl::layout().
     m_geometryNeedsUpdate = true;
 }
 
 WebLayer* LinkHighlight::layer()
 {
     return clipLayer();
 }
 
 } // namespace blink