[ 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 cd07aa30ef859ee7d59b7dbc96a1a43bc501a7fb..a94639e76b72f9af5f34a9bb41fae2ebedb5e993 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -96,6 +96,7 @@
 #include "wtf/Vector.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/StringBuilder.h"
+#include <inttypes.h>
 
 namespace blink {
 
@@ -766,6 +767,22 @@ void Node::markAncestorsWithChildNeedsStyleRecalc()
     document().scheduleRenderTreeUpdateIfNeeded();
 }
 
+PassRefPtr<TraceEvent::ConvertableToTraceFormat> jsonObjectForTracedStyleInvalidation(const Node* node, const StyleChangeType styleChangeType)
+{
+    RefPtr<TracedValue> value = TracedValue::create();
+    value->setString("root_node", node->debugName());
+    LocalFrame* frame = node->document().frame();
+    value->setString("frame", String::format("0x%" PRIx64, static_cast<uint64>(reinterpret_cast<intptr_t>(frame))));
+    switch(styleChangeType) {
+        case(NoStyleChange): value->setString("styleChange", "NoStyleChange"); break;
+        case(LocalStyleChange): value->setString("styleChange", "LocalStyleChange"); break;
+        case(SubtreeStyleChange): value->setString("styleChange", "SubtreeStyleChange"); break;
+        case(NeedsReattachStyleChange): value->setString("styleChange", "NeedsReattachStyleChange"); break;
+        default: value->setString("styleChange", "Unknown");
+    }
+    return value;
+}
+
 void Node::setNeedsStyleRecalc(StyleChangeType changeType)
 {
     ASSERT(changeType != NoStyleChange);
@@ -777,6 +794,7 @@ void Node::setNeedsStyleRecalc(StyleChangeType changeType)
         setStyleChange(changeType);
         if (changeType >= SubtreeStyleChange)
             traceStyleChangeIfNeeded(changeType);
+        TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.invalidations"), "Invalidation", "data", jsonObjectForTracedStyleInvalidation(this, changeType));
     }
 
     if (existingChangeType == NoStyleChange)