[Invalidation Tracking] Trace StyleInvalidator 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..08fe2866f136c877b66815e3f7e9f70f94cffbd9 100644
--- a/Source/core/css/invalidation/StyleInvalidator.cpp
+++ b/Source/core/css/invalidation/StyleInvalidator.cpp
@@ -13,6 +13,7 @@
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/shadow/ElementShadow.h"
 #include "core/dom/shadow/ShadowRoot.h"
+#include "core/inspector/InspectorTraceEvents.h"
 #include "core/rendering/RenderObject.h"
 
 namespace blink {
@@ -86,8 +87,10 @@ bool StyleInvalidator::RecursionData::matchesCurrentInvalidationSets(Element& el
 {
     ASSERT(!m_wholeSubtreeInvalid);
 
-    if (m_invalidateCustomPseudo && element.shadowPseudoId() != nullAtom)
+    if (m_invalidateCustomPseudo && element.shadowPseudoId() != nullAtom) {
+        TRACE_STYLE_INVALIDATOR_INVALIDATION(element, InvalidateCustomPseudo);
         return true;
+    }
 
     for (InvalidationSets::iterator it = m_invalidationSets.begin(); it != m_invalidationSets.end(); ++it) {
         if ((*it)->invalidatesElement(element))
@@ -108,9 +111,13 @@ bool StyleInvalidator::checkInvalidationSetsAgainstElement(Element& element, Sty
             for (InvalidationList::const_iterator it = invalidationList->begin(); it != invalidationList->end(); ++it)
                 recursionData.pushInvalidationSet(**it);
             // FIXME: It's really only necessary to clone the render style for this element, not full style recalc.
+            TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.invalidationTracking"),

[pdr., 2014/09/30 02:08:49]

Can you add a newline here so it's clear the comment and trace event are
unrelated?

[kouhei (in TOK), 2014/09/30 02:22:00]

I think this comment is related. IIUC, theoretically we don't need to
setNeedsStyleRecalcStyle here, as the element might not match the current
invalidation set. This is forcing styleRecalc to disable RenderStyle sharing for
the element.

+                "StyleInvalidatorInvalidationTracking",
+                "data", InspectorStyleInvalidatorInvalidateEvent::invalidationList(element, *invalidationList));
             return true;
         }
     }
+
     return recursionData.matchesCurrentInvalidationSets(element);
 }
 
@@ -148,10 +155,12 @@ bool StyleInvalidator::invalidate(Element& element, StyleInvalidator::RecursionD
         element.setNeedsStyleRecalc(recursionData.wholeSubtreeInvalid() ? SubtreeStyleChange : LocalStyleChange);
     } 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())
+        if (RenderObject* renderer = element.renderer()) {
             renderer->setStyleInternal(RenderStyle::clone(renderer->style()));
-        else
+        } else {
+            TRACE_STYLE_INVALIDATOR_INVALIDATION(element, PreventStyleSharingForParent);
             element.setNeedsStyleRecalc(LocalStyleChange);
+        }
     }
 
     element.clearChildNeedsStyleInvalidation();