[Invalidation Tracking] add TraceEvents for setNeedsStyleRecalc.

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 694 matching lines @@
         p->setChildNeedsStyleRecalc();
     document().scheduleRenderTreeUpdateIfNeeded();
 }
 
 void Node::setNeedsStyleRecalc(StyleChangeType changeType, const StyleChangeReasonForTracing& reason)
 {
     ASSERT(changeType != NoStyleChange);
     if (!inActiveDocument())
         return;
 
+    TRACE_EVENT_INSTANT1(
+        TRACE_DISABLED_BY_DEFAULT("devtools.timeline.invalidationTracking"),
+        "StyleRecalcInvalidationTracking",
+        "data",
+        InspectorStyleRecalcInvalidationTrackingEvent::data(this, reason));
+
     StyleChangeType existingChangeType = styleChangeType();
     if (changeType > existingChangeType)
         setStyleChange(changeType);
 
     if (existingChangeType == NoStyleChange)
         markAncestorsWithChildNeedsStyleRecalc();
 
     if (isElementNode() && hasRareData())
         toElement(*this).setAnimationStyleChange(false);
 }
@@ skipping 1721 matching lines @@
         node->showTreeForThis();
 }
 
 void showNodePath(const blink::Node* node)
 {
     if (node)
         node->showNodePathForThis();
 }
 
 #endif