Eliminate recursion in SVGTextMetricsBuilder::walkTree

Source/core/rendering/svg/SVGTextMetricsBuilder.cpp

 /*
  * Copyright (C) Research In Motion Limited 2010-2012. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 165 matching lines @@
 
     if (!data->allCharactersMap)
         return;
 
     data->valueListPosition += m_textPosition - data->skippedCharacters;
     data->skippedCharacters = 0;
 }
 
 void SVGTextMetricsBuilder::walkTree(RenderObject* start, RenderSVGInlineText* stopAtLeaf, MeasureTextData* data)
 {
-    for (RenderObject* child = start->firstChild(); child; child = child->nextSibling()) {
+    RenderObject* child = start->firstChild();
+    while (child) {
         if (child->isSVGInlineText()) {
             RenderSVGInlineText* text = toRenderSVGInlineText(child);
-            if (stopAtLeaf && stopAtLeaf != text) {
-                data->processRenderer = false;
-                measureTextRenderer(text, data);
+            data->processRenderer = !stopAtLeaf || stopAtLeaf == text;
+            measureTextRenderer(text, data);
+            if (stopAtLeaf && stopAtLeaf == text)
+                return;
+        } else if (child->isSVGInline()) {
+            // Visit children of text content elements.
+            if (RenderObject* inlineChild = child->firstChild()) {
+                child = inlineChild;
                 continue;
             }
-
-            data->processRenderer = true;
-            measureTextRenderer(text, data);
-            if (stopAtLeaf)
-                return;
-
-            continue;
         }
-
-        if (!child->isSVGInline())
-            continue;
-
-        walkTree(child, stopAtLeaf, data);
+        child = child->nextInPreOrderAfterChildren(start);
     }
 }
 
 void SVGTextMetricsBuilder::measureTextRenderer(RenderSVGInlineText* text)
 {
     ASSERT(text);
 
     RenderSVGText* textRoot = RenderSVGText::locateRenderSVGTextAncestor(text);
     if (!textRoot)
         return;
 
     MeasureTextData data(0);
     walkTree(textRoot, text, &data);
 }
 
 void SVGTextMetricsBuilder::buildMetricsAndLayoutAttributes(RenderSVGText* textRoot, RenderSVGInlineText* stopAtLeaf, SVGCharacterDataMap& allCharactersMap)
 {
     ASSERT(textRoot);
     MeasureTextData data(&allCharactersMap);
     walkTree(textRoot, stopAtLeaf, &data);
 }
 
 }