[ Do not submit ] Prototype for invalidation analysis

Source/core/dom/Node.cpp

Index: Source/core/dom/Node.cpp
diff --git a/Source/core/dom/Node.cpp b/Source/core/dom/Node.cpp
index 86b776ca6635bcd78088e9361e474924b4363aff..d8750b9abc036c139652599cb7356d4b1ba258e8 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -79,6 +79,7 @@
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/HTMLStyleElement.h"
+#include "core/inspector/InspectorTraceEvents.h"
 #include "core/page/ContextMenuController.h"
 #include "core/page/EventHandler.h"
 #include "core/page/Page.h"
@@ -775,6 +776,11 @@ void Node::setNeedsStyleRecalc(StyleChangeType changeType)
         setStyleChange(changeType);
         if (changeType >= SubtreeStyleChange)
             traceStyleChangeIfNeeded(changeType);
+        TRACE_EVENT_INSTANT1(
+            TRACE_DISABLED_BY_DEFAULT("devtools.timeline.styleInvalidationTracking"),

[caseq, 2014/08/26 12:19:07]

nit: I wonder if category needs to be that specific (i.e. can we just have
devtools.timeline.invalidations, or will we have the analysis of different types
of invalidations independently)?

+            "StyleInvalidationTracking",
+            "data",
+            InspectorStyleInvalidationTrackingEvent::data(this));
     }
 
     if (existingChangeType == NoStyleChange)