[Invalidation Tracking] Trace StyleInvalidator setNeedsStyleRecalc

Source/core/css/invalidation/DescendantInvalidationSet.cpp

Index: Source/core/css/invalidation/DescendantInvalidationSet.cpp
diff --git a/Source/core/css/invalidation/DescendantInvalidationSet.cpp b/Source/core/css/invalidation/DescendantInvalidationSet.cpp
index 232f3cfe9b14348d607baf9ee7162d9ea459874d..d8ba4ec93637afc815afe81539edb749627bc13f 100644
--- a/Source/core/css/invalidation/DescendantInvalidationSet.cpp
+++ b/Source/core/css/invalidation/DescendantInvalidationSet.cpp
@@ -33,6 +33,9 @@
 
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/Element.h"
+#include "core/inspector/InspectorTraceEvents.h"
+#include "platform/TracedValue.h"
+#include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
@@ -48,24 +51,32 @@ bool DescendantInvalidationSet::invalidatesElement(Element& element) const
     if (m_allDescendantsMightBeInvalid)
         return true;
 
-    if (m_tagNames && m_tagNames->contains(element.tagQName().localName()))
+    if (m_tagNames && m_tagNames->contains(element.tagQName().localName())) {
+        TRACE_STYLE_INVALIDATOR_INVALIDATION_SELECTORPART(element, InvalidationSetMatchedTagName, element.tagQName().localName());
         return true;
+    }
 
-    if (element.hasID() && m_ids && m_ids->contains(element.idForStyleResolution()))
+    if (element.hasID() && m_ids && m_ids->contains(element.idForStyleResolution())) {
+        TRACE_STYLE_INVALIDATOR_INVALIDATION_SELECTORPART(element, InvalidationSetMatchedId, element.idForStyleResolution());
         return true;
+    }
 
     if (element.hasClass() && m_classes) {
         const SpaceSplitString& classNames = element.classNames();
         for (WillBeHeapHashSet<AtomicString>::const_iterator it = m_classes->begin(); it != m_classes->end(); ++it) {
-            if (classNames.contains(*it))
+            if (classNames.contains(*it)) {
+                TRACE_STYLE_INVALIDATOR_INVALIDATION_SELECTORPART(element, InvalidationSetMatchedClass, *it);
                 return true;
+            }
         }
     }
 
     if (element.hasAttributes() && m_attributes) {
         for (WillBeHeapHashSet<AtomicString>::const_iterator it = m_attributes->begin(); it != m_attributes->end(); ++it) {
-            if (element.hasAttribute(*it))
+            if (element.hasAttribute(*it)) {
+                TRACE_STYLE_INVALIDATOR_INVALIDATION_SELECTORPART(element, InvalidationSetMatchedAttribute, *it);
                 return true;
+            }
         }
     }
 
@@ -193,33 +204,60 @@ void DescendantInvalidationSet::trace(Visitor* visitor)
 #endif
 }
 
-#ifndef NDEBUG
-void DescendantInvalidationSet::show() const
+void DescendantInvalidationSet::toTracedValue(TracedValue* value) const
 {
-    fprintf(stderr, "DescendantInvalidationSet { ");
+    value->beginArray();
+
     if (m_allDescendantsMightBeInvalid)
-        fprintf(stderr, "* ");
+        value->pushString("*");

[caseq, 2014/10/01 07:50:49]

Can we please get it more structured -- i.e. instead of custom-encoded  string,
use a JSON object? I realize current format is tailored after show() where it
was more human-readable, but now that we expose this thorough DevTools, I think
we should make it more convenient to process programmatically (and I hope that
once this is supported in DevTools, the debug output will no longer be
necessary).

[kouhei (in TOK), 2014/10/02 02:16:46]

Done.

     if (m_customPseudoInvalid)
-        fprintf(stderr, "::custom ");
+        value->pushString("::custom");
     if (m_treeBoundaryCrossing)
-        fprintf(stderr, "::shadow/deep/ ");
+        value->pushString("::shadow/deep/");
     if (m_ids) {
-        for (WillBeHeapHashSet<AtomicString>::const_iterator it = m_ids->begin(); it != m_ids->end(); ++it)
-            fprintf(stderr, "#%s ", (*it).ascii().data());
+        for (const auto& id : *m_ids) {
+            StringBuilder builder;
+            builder.append("#");
+            builder.append(id);
+            value->pushString(builder.toString());
+        }
     }
     if (m_classes) {
-        for (WillBeHeapHashSet<AtomicString>::const_iterator it = m_classes->begin(); it != m_classes->end(); ++it)
-            fprintf(stderr, ".%s ", (*it).ascii().data());
+        for (const auto& className : *m_classes) {
+            StringBuilder builder;
+            builder.append(".");
+            builder.append(className);
+            value->pushString(builder.toString());
+        }
     }
     if (m_tagNames) {
-        for (WillBeHeapHashSet<AtomicString>::const_iterator it = m_tagNames->begin(); it != m_tagNames->end(); ++it)
-            fprintf(stderr, "<%s> ", (*it).ascii().data());
+        for (const auto& tagName : *m_tagNames) {
+            StringBuilder builder;
+            builder.append("<");
+            builder.append(tagName);
+            builder.append(">");
+            value->pushString(builder.toString());
+        }
     }
     if (m_attributes) {
-        for (WillBeHeapHashSet<AtomicString>::const_iterator it = m_attributes->begin(); it != m_attributes->end(); ++it)
-            fprintf(stderr, "[%s] ", (*it).ascii().data());
+        for (const auto& attribute : *m_attributes) {
+            StringBuilder builder;
+            builder.append("[");
+            builder.append(attribute);
+            builder.append("]");
+            value->pushString(builder.toString());
+        }
     }
-    fprintf(stderr, "}\n");
+
+    value->endArray();
+}
+
+#ifndef NDEBUG
+void DescendantInvalidationSet::show() const
+{
+    RefPtr<TracedValue> value = TracedValue::create();
+    toTracedValue(value.get());
+    fprintf(stderr, "%s\n", value->asTraceFormat().ascii().data());
 }
 #endif // NDEBUG