Track reasons for |Node::SetNeedsStyleRecalc|

Source/core/css/invalidation/StyleInvalidator.cpp

Index: Source/core/css/invalidation/StyleInvalidator.cpp
diff --git a/Source/core/css/invalidation/StyleInvalidator.cpp b/Source/core/css/invalidation/StyleInvalidator.cpp
index e237c9ae1a70081d237e993b3b6c134eea328f2d..4f2b98c4f2a42cdbedc280a4bee7dee5ac35b355 100644
--- a/Source/core/css/invalidation/StyleInvalidator.cpp
+++ b/Source/core/css/invalidation/StyleInvalidator.cpp
@@ -145,13 +145,13 @@ bool StyleInvalidator::invalidate(Element& element, StyleInvalidator::RecursionD
         someChildrenNeedStyleRecalc = invalidateChildren(element, recursionData);
 
     if (thisElementNeedsStyleRecalc) {
-        element.setNeedsStyleRecalc(recursionData.wholeSubtreeInvalid() ? SubtreeStyleChange : LocalStyleChange);
+        element.setNeedsStyleRecalc(StyleChangeReasonForTracing::StyleInvalidator, recursionData.wholeSubtreeInvalid() ? SubtreeStyleChange : LocalStyleChange);

[esprehn, 2014/09/19 04:53:09]

I'm not sure this is really adding value for developers. StyleInvalidator could
be class, id, pseudo or any number of other changes.

[kouhei (in TOK), 2014/09/22 09:03:54]

This is to be addressed in next CL. I’m adding TraceEvents in StyleInvalidator
and setNeedsStyleInvalidation too. When the devtools post processing finds this
TraceEvent, it will search for matching StyleInvalidator TraceEvent with the
class/id/pseudo/attr info.

     } else if (recursionData.hasInvalidationSets() && someChildrenNeedStyleRecalc) {
         // Clone the RenderStyle in order to preserve correct style sharing, if possible. Otherwise recalc style.
         if (RenderObject* renderer = element.renderer())
             renderer->setStyleInternal(RenderStyle::clone(renderer->style()));
         else
-            element.setNeedsStyleRecalc(LocalStyleChange);
+            element.setNeedsStyleRecalc(StyleChangeReasonForTracing::StyleInvalidator, LocalStyleChange);
     }
 
     element.clearChildNeedsStyleInvalidation();