[LazyParseCSS] Add histogram for rule usage %

third_party/WebKit/Source/core/css/parser/CSSParserImpl.cpp

Index: third_party/WebKit/Source/core/css/parser/CSSParserImpl.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSParserImpl.cpp b/third_party/WebKit/Source/core/css/parser/CSSParserImpl.cpp
index b87180927300e20a5e04c826bc74dcce8fc98ef4..8140d02235f04667b22f7652a4f904c7be29cfac 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSParserImpl.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSParserImpl.cpp
@@ -801,9 +801,8 @@ StyleRule* CSSParserImpl::consumeStyleRule(CSSParserTokenRange prelude,
   } else if (m_lazyState &&
              m_lazyState->shouldLazilyParseProperties(selectorList, block)) {
     DCHECK(m_styleSheet);
-    return StyleRule::createLazy(
-        std::move(selectorList),
-        new CSSLazyPropertyParserImpl(block, m_lazyState));
+    return StyleRule::createLazy(std::move(selectorList),
+                                 m_lazyState->createLazyParser(block));
   }
   consumeDeclarationList(block, StyleRule::Style);