[LazyParseCSS] Ensure UseCounting has parity with strict parsing

third_party/WebKit/Source/core/css/parser/CSSLazyParsingState.h

Index: third_party/WebKit/Source/core/css/parser/CSSLazyParsingState.h
diff --git a/third_party/WebKit/Source/core/css/parser/CSSLazyParsingState.h b/third_party/WebKit/Source/core/css/parser/CSSLazyParsingState.h
index 3234141f9e8102319f61a3445b02234ad56bf2a3..c481f9a6d26ed61766c44002ad9e2e6037e30263 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSLazyParsingState.h
+++ b/third_party/WebKit/Source/core/css/parser/CSSLazyParsingState.h
@@ -31,7 +31,7 @@ class CSSLazyParsingState
   bool shouldLazilyParseProperties(const CSSSelectorList&,
                                    const CSSParserTokenRange& block);
 
-  DEFINE_INLINE_TRACE() { visitor->trace(m_owningContents); }
+  DECLARE_TRACE();
 
  private:
   CSSParserContext m_context;
@@ -42,6 +42,10 @@ class CSSLazyParsingState
   // Weak to ensure lazy state will never cause the contents to live longer than
   // it should (we DCHECK this fact).
   WeakMember<StyleSheetContents> m_owningContents;
+
+  // Cache the document as a proxy for caching the UseCounter. Grabbing the
+  // UseCounter per every property parse is a bit more expensive.
+  WeakMember<Document> m_document;
 };
 
 }  // namespace blink