[LazyParseCSS] WIP Implement token discarding

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/parser/CSSLazyParsingState.h"
 #include "core/css/parser/CSSLazyPropertyParserImpl.h"
 #include "core/css/parser/CSSParserTokenRange.h"
 #include "core/dom/Document.h"
 #include "core/frame/UseCounter.h"
 #include "platform/Histogram.h"
 
 namespace blink {
 
 CSSLazyParsingState::CSSLazyParsingState(const CSSParserContext* context,
                                          Vector<String> escapedStrings,
                                          const String& sheetText,
                                          StyleSheetContents* contents)
     : m_context(context),
-      m_escapedStrings(std::move(escapedStrings)),
       m_sheetText(sheetText),
       m_owningContents(contents),
       m_parsedStyleRules(0),
       m_totalStyleRules(0),
       m_styleRulesNeededForNextMilestone(0),
       m_usage(UsageGe0),
-      m_shouldUseCount(m_context->isUseCounterRecordingEnabled()) {}
+      m_shouldUseCount(m_context->isUseCounterRecordingEnabled()) {
+  m_escapedStrings.reserveCapacityForSize(escapedStrings.size());
+  for (const auto& escapedString : escapedStrings) {
+    m_escapedStrings.insert(escapedString.impl()->bytes(), escapedString);
+  }
+}
 
 void CSSLazyParsingState::finishInitialParsing() {
   recordUsageMetrics();
 }
 
 CSSLazyPropertyParserImpl* CSSLazyParsingState::createLazyParser(
     const CSSParserTokenRange& block) {
   ++m_totalStyleRules;
   return new CSSLazyPropertyParserImpl(std::move(block), this);
 }
@@ skipping 45 matching lines @@
       const CSSSelector::PseudoType type(current->getPseudoType());
       if (type == CSSSelector::PseudoBefore || type == CSSSelector::PseudoAfter)
         return false;
       if (current->relation() != CSSSelector::SubSelector)
         break;
     }
   }
   return true;
 }
 
+bool CSSLazyParsingState::tokenBackingUsesEscapedString(
+    const void* tokenBackingBytes) {
+  return m_escapedStrings.contains(tokenBackingBytes);
+}
+
 void CSSLazyParsingState::recordUsageMetrics() {
   DEFINE_STATIC_LOCAL(EnumerationHistogram, usageHistogram,
                       ("Style.LazyUsage.Percent", UsageLastValue));
   DEFINE_STATIC_LOCAL(CustomCountHistogram, totalRulesHistogram,
                       ("Style.TotalLazyRules", 0, 100000, 50));
   DEFINE_STATIC_LOCAL(CustomCountHistogram, totalRulesFullUsageHistogram,
                       ("Style.TotalLazyRules.FullUsage", 0, 100000, 50));
   switch (m_usage) {
     case UsageGe0:
       totalRulesHistogram.count(m_totalStyleRules);
@@ skipping 23 matching lines @@
   usageHistogram.count(m_usage);
 }
 
 DEFINE_TRACE(CSSLazyParsingState) {
   visitor->trace(m_owningContents);
   visitor->trace(m_document);
   visitor->trace(m_context);
 }
 
 }  // namespace blink