Lazy Parse CSS

third_party/WebKit/Source/core/css/StyleRule.cpp

Index: third_party/WebKit/Source/core/css/StyleRule.cpp
diff --git a/third_party/WebKit/Source/core/css/StyleRule.cpp b/third_party/WebKit/Source/core/css/StyleRule.cpp
index ffc73fe80bc83c10d6dd96c826c9646bb7d9eb7e..2c595b9333e078f25e0b6cf3841ffbac6deeed31 100644
--- a/third_party/WebKit/Source/core/css/StyleRule.cpp
+++ b/third_party/WebKit/Source/core/css/StyleRule.cpp
@@ -212,15 +212,31 @@ unsigned StyleRule::averageSizeInBytes()
 
 StyleRule::StyleRule(CSSSelectorList selectorList, StylePropertySet* properties)
     : StyleRuleBase(Style)
+    , m_selectorList(std::move(selectorList))
     , m_properties(properties)
 {
-    m_selectorList = std::move(selectorList);
+}
+
+StyleRule::StyleRule(CSSSelectorList selectorList, std::unique_ptr<DeferredPropertiesClosure> deferredProperties)
+    : StyleRuleBase(Style)
+    , m_selectorList(std::move(selectorList))
+    , m_deferred(std::move(deferredProperties))
+{
+}
+
+const StylePropertySet& StyleRule::properties() const
+{
+    if (!m_properties) {
+        m_properties = (*m_deferred)();
+        m_deferred.reset();
+    }
+    return *m_properties;
 }
 
 StyleRule::StyleRule(const StyleRule& o)
     : StyleRuleBase(o)
-    , m_properties(o.m_properties->mutableCopy())
     , m_selectorList(o.m_selectorList.copy())
+    , m_properties(o.properties().mutableCopy())
 {
 }
 
@@ -230,11 +246,24 @@ StyleRule::~StyleRule()
 
 MutableStylePropertySet& StyleRule::mutableProperties()
 {
-    if (!m_properties->isMutable())
+    // Ensure m_properties is initialized.
+    if (!properties().isMutable())
         m_properties = m_properties->mutableCopy();
     return *toMutableStylePropertySet(m_properties.get());
 }
 
+bool StyleRule::propertiesHaveFailedOrCanceledSubresources() const
+{
+    return m_properties && m_properties->hasFailedOrCanceledSubresources();
+}
+
+bool StyleRule::shouldConsiderForMatchingRules(bool includeEmptyRules) const
+{
+    // Consider all non-empty property sets if parsing has not been deferred.
+    // Otherwise, consider all StyleRules with non-null deferred closures.
+    return includeEmptyRules || !(m_properties && m_properties->isEmpty());
+}
+
 DEFINE_TRACE_AFTER_DISPATCH(StyleRule)
 {
     visitor->trace(m_properties);