Make CSSParserContext be garbage collected.

third_party/WebKit/Source/core/css/parser/CSSParserContext.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/CSSParserContext.h"
 
+#include "core/css/CSSStyleSheet.h"
+#include "core/css/StyleSheetContents.h"
 #include "core/frame/Settings.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/html/imports/HTMLImportsController.h"
 
 namespace blink {
 
-CSSParserContext::CSSParserContext(CSSParserMode mode,
-                                   UseCounter* useCounter,
-                                   SelectorProfile profile)
+// static
+CSSParserContext* CSSParserContext::create(const CSSParserContext* other,
+                                           const CSSStyleSheet* styleSheet) {
+  return new CSSParserContext(other, UseCounter::getFrom(styleSheet));
+}
+
+// static
+CSSParserContext* CSSParserContext::create(
+    const CSSParserContext* other,
+    const StyleSheetContents* styleSheetContents) {
+  return new CSSParserContext(other, UseCounter::getFrom(styleSheetContents));
+}
+
+CSSParserContext::CSSParserContext(CSSParserMode mode, SelectorProfile profile)
     : m_mode(mode),
       m_matchMode(mode),
       m_profile(profile),
       m_isHTMLDocument(false),
       m_useLegacyBackgroundSizeShorthandBehavior(false),
       m_shouldCheckContentSecurityPolicy(DoNotCheckContentSecurityPolicy),
-      m_useCounter(useCounter) {}
+      m_useCounter(nullptr) {}
 
 CSSParserContext::CSSParserContext(const Document& document,
-                                   UseCounter* useCounter,
                                    const KURL& baseURL,
                                    const String& charset,
                                    SelectorProfile profile)
     : m_baseURL(baseURL.isNull() ? document.baseURL() : baseURL),
       m_charset(charset),
       m_mode(document.inQuirksMode() ? HTMLQuirksMode : HTMLStandardMode),
       m_profile(profile),
       m_referrer(m_baseURL.strippedForUseAsReferrer(),
                  document.getReferrerPolicy()),
       m_isHTMLDocument(document.isHTMLDocument()),
       m_useLegacyBackgroundSizeShorthandBehavior(
           document.settings()
               ? document.settings()
                     ->getUseLegacyBackgroundSizeShorthandBehavior()
               : false),
       m_shouldCheckContentSecurityPolicy(DoNotCheckContentSecurityPolicy),
-      m_useCounter(useCounter) {
+      m_useCounter(nullptr) {
   if (ContentSecurityPolicy::shouldBypassMainWorld(&document))
     m_shouldCheckContentSecurityPolicy = DoNotCheckContentSecurityPolicy;
   else
     m_shouldCheckContentSecurityPolicy = CheckContentSecurityPolicy;
 
   if (HTMLImportsController* importsController = document.importsController()) {
     m_matchMode = importsController->master()->inQuirksMode()
                       ? HTMLQuirksMode
                       : HTMLStandardMode;
   } else {
     m_matchMode = m_mode;
   }
 }
 
-CSSParserContext::CSSParserContext(const CSSParserContext& other,
+CSSParserContext::CSSParserContext(const CSSParserContext* other,
                                    UseCounter* useCounter)
-    : m_baseURL(other.m_baseURL),
-      m_charset(other.m_charset),
-      m_mode(other.m_mode),
-      m_matchMode(other.m_matchMode),
-      m_profile(other.m_profile),
-      m_referrer(other.m_referrer),
-      m_isHTMLDocument(other.m_isHTMLDocument),
+    : m_baseURL(other->m_baseURL),
+      m_charset(other->m_charset),
+      m_mode(other->m_mode),
+      m_matchMode(other->m_matchMode),
+      m_profile(other->m_profile),
+      m_referrer(other->m_referrer),
+      m_isHTMLDocument(other->m_isHTMLDocument),
       m_useLegacyBackgroundSizeShorthandBehavior(
-          other.m_useLegacyBackgroundSizeShorthandBehavior),
+          other->m_useLegacyBackgroundSizeShorthandBehavior),
       m_shouldCheckContentSecurityPolicy(
-          other.m_shouldCheckContentSecurityPolicy),
+          other->m_shouldCheckContentSecurityPolicy),
       m_useCounter(useCounter) {}
 
 bool CSSParserContext::operator==(const CSSParserContext& other) const {
   return m_baseURL == other.m_baseURL && m_charset == other.m_charset &&
          m_mode == other.m_mode && m_matchMode == other.m_matchMode &&
          m_profile == other.m_profile &&
          m_isHTMLDocument == other.m_isHTMLDocument &&
          m_useLegacyBackgroundSizeShorthandBehavior ==
              other.m_useLegacyBackgroundSizeShorthandBehavior;
 }
 
-const CSSParserContext& strictCSSParserContext() {
+const CSSParserContext* strictCSSParserContext() {
   DEFINE_STATIC_LOCAL(CSSParserContext, strictContext,
-                      (HTMLStandardMode, nullptr));
-  return strictContext;
+                      (new CSSParserContext(HTMLStandardMode)));
+  return &strictContext;

[haraken, 2017/01/12 04:51:13]

Or you can change the type of the return value to CSSParserContext&, since the
return value is guaranteed to be not null.

[Bret, 2017/01/13 02:15:28]

I think this is okay, as long as it isn't wrong. This way CSSParserContext is a
pointer everywhere.

 }
 
 KURL CSSParserContext::completeURL(const String& url) const {
   if (url.isNull())
     return KURL();
   if (charset().isEmpty())
     return KURL(baseURL(), url);
   return KURL(baseURL(), url, charset());
 }
 
 }  // namespace blink