Introduce builders for tracing event arguments

Source/core/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 678 matching lines @@
 
 void Node::markAncestorsWithChildNeedsDistributionRecalc()
 {
     for (Node* node = this; node && !node->childNeedsDistributionRecalc(); node = node->parentOrShadowHostNode())
         node->setChildNeedsDistributionRecalc();
     document().scheduleRenderTreeUpdateIfNeeded();
 }
 
 namespace {
 
-PassRefPtr<JSONArray> jsStackAsJSONArray()
+void addJsStack(TracedArray<TracedValue>& stackFrames)
 {
-    RefPtr<JSONArray> jsonArray = JSONArray::create();
     RefPtrWillBeRawPtr<ScriptCallStack> stack = createScriptCallStack(10);
     if (!stack)
-        return jsonArray.release();
+        return;
     for (size_t i = 0; i < stack->size(); i++)
-        jsonArray->pushString(stack->at(i).functionName());
-    return jsonArray.release();
+        stackFrames.pushString(stack->at(i).functionName());
 }
 
-PassRefPtr<JSONObject> jsonObjectForStyleInvalidation(unsigned nodeCount, const Node* rootNode)
+PassRefPtr<TraceEvent::ConvertableToTraceFormat> jsonObjectForStyleInvalidation(unsigned nodeCount, const Node* rootNode)
 {
-    RefPtr<JSONObject> jsonObject = JSONObject::create();
-    jsonObject->setNumber("node_count", nodeCount);
-    jsonObject->setString("root_node", rootNode->debugName());
-    jsonObject->setArray("js_stack", jsStackAsJSONArray());
-    return jsonObject.release();
+    TracedValue value;
+    value.setInteger("node_count", nodeCount);
+    value.setString("root_node", rootNode->debugName());
+    TracedArray<TracedValue>& array = value.beginArray("js_stack");
+    addJsStack(array);
+    array.endArray();
+    return value.finish();
 }
 
 } // anonymous namespace'd functions supporting traceStyleChange
 
 unsigned Node::styledSubtreeSize() const
 {
     unsigned nodeCount = 0;
 
     for (const Node* node = this; node; node = NodeTraversal::next(*node, this)) {
         if (node->isTextNode() || node->isElementNode())
             nodeCount++;
         for (ShadowRoot* root = node->youngestShadowRoot(); root; root = root->olderShadowRoot())
             nodeCount += root->styledSubtreeSize();
     }
 
     return nodeCount;
 }
 
 void Node::traceStyleChange(StyleChangeType changeType)
 {
     static const unsigned kMinLoggedSize = 100;
     unsigned nodeCount = styledSubtreeSize();
     if (nodeCount < kMinLoggedSize)
         return;
 
     TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("style.debug"),
         "Node::setNeedsStyleRecalc",
-        "data", TracedValue::fromJSONValue(jsonObjectForStyleInvalidation(nodeCount, this))
+        "data", jsonObjectForStyleInvalidation(nodeCount, this)
     );
 }
 
 void Node::traceStyleChangeIfNeeded(StyleChangeType changeType)
 {
     // TRACE_EVENT_CATEGORY_GROUP_ENABLED macro loads a global static bool into our local bool.
     bool styleTracingEnabled;
     TRACE_EVENT_CATEGORY_GROUP_ENABLED(TRACE_DISABLED_BY_DEFAULT("style.debug"), &styleTracingEnabled);
     if (UNLIKELY(styleTracingEnabled))
         traceStyleChange(changeType);
@@ skipping 1817 matching lines @@
         node->showTreeForThis();
 }
 
 void showNodePath(const WebCore::Node* node)
 {
     if (node)
         node->showNodePathForThis();
 }
 
 #endif