Don't generate RuleSets for viewport UA sheets.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
@@ skipping 55 matching lines @@
 static StyleSheetContents* parseUASheet(const String& str) {
   StyleSheetContents* sheet =
       StyleSheetContents::create(CSSParserContext(UASheetMode, nullptr));
   sheet->parseString(str);
   // User Agent stylesheets are parsed once for the lifetime of the renderer
   // process and are intentionally leaked.
   LEAK_SANITIZER_IGNORE_OBJECT(sheet);
   return sheet;
 }
 
-CSSDefaultStyleSheets::CSSDefaultStyleSheets()
-    : m_defaultStyle(nullptr),
-      m_defaultMobileViewportStyle(nullptr),
-      m_defaultTelevisionViewportStyle(nullptr),
-      m_defaultQuirksStyle(nullptr),
-      m_defaultPrintStyle(nullptr),
-      m_defaultViewSourceStyle(nullptr),
-      m_defaultXHTMLMobileProfileStyle(nullptr),
-      m_defaultStyleSheet(nullptr),
-      m_mobileViewportStyleSheet(nullptr),
-      m_televisionViewportStyleSheet(nullptr),
-      m_quirksStyleSheet(nullptr),
-      m_svgStyleSheet(nullptr),
-      m_mathmlStyleSheet(nullptr),
-      m_mediaControlsStyleSheet(nullptr),
-      m_fullscreenStyleSheet(nullptr) {
+CSSDefaultStyleSheets::CSSDefaultStyleSheets() {
   m_defaultStyle = RuleSet::create();
   m_defaultPrintStyle = RuleSet::create();
   m_defaultQuirksStyle = RuleSet::create();
 
   // Strict-mode rules.
   String defaultRules = loadResourceAsASCIIString("html.css") +
                         LayoutTheme::theme().extraDefaultStyleSheet();
   m_defaultStyleSheet = parseUASheet(defaultRules);
   m_defaultStyle->addRulesFromSheet(defaultStyleSheet(), screenEval());
   m_defaultPrintStyle->addRulesFromSheet(defaultStyleSheet(), printEval());
 
   // Quirks-mode rules.
   String quirksRules = loadResourceAsASCIIString("quirks.css") +
                        LayoutTheme::theme().extraQuirksStyleSheet();
   m_quirksStyleSheet = parseUASheet(quirksRules);
   m_defaultQuirksStyle->addRulesFromSheet(quirksStyleSheet(), screenEval());
 }
 
 RuleSet* CSSDefaultStyleSheets::defaultViewSourceStyle() {
   if (!m_defaultViewSourceStyle) {
     m_defaultViewSourceStyle = RuleSet::create();
     // Loaded stylesheet is leaked on purpose.
     StyleSheetContents* stylesheet =
         parseUASheet(loadResourceAsASCIIString("view-source.css"));
     m_defaultViewSourceStyle->addRulesFromSheet(stylesheet, screenEval());
   }
-  return m_defaultViewSourceStyle.get();
+  return m_defaultViewSourceStyle;
 }
 
-RuleSet* CSSDefaultStyleSheets::defaultXHTMLMobileProfileStyle() {
-  if (!m_defaultXHTMLMobileProfileStyle) {
-    m_defaultXHTMLMobileProfileStyle = RuleSet::create();
-    // Loaded stylesheet is leaked on purpose.
-    StyleSheetContents* stylesheet =
+StyleSheetContents*
+CSSDefaultStyleSheets::ensureXHTMLMobileProfileStyleSheet() {
+  if (!m_xhtmlMobileProfileStyleSheet)
+    m_xhtmlMobileProfileStyleSheet =
         parseUASheet(loadResourceAsASCIIString("xhtmlmp.css"));
-    m_defaultXHTMLMobileProfileStyle->addRulesFromSheet(stylesheet,
-                                                        screenEval());
-  }
-  return m_defaultXHTMLMobileProfileStyle.get();
+  return m_xhtmlMobileProfileStyleSheet;
 }
 
-RuleSet* CSSDefaultStyleSheets::defaultMobileViewportStyle() {
-  if (!m_defaultMobileViewportStyle) {
-    m_defaultMobileViewportStyle = RuleSet::create();
+StyleSheetContents* CSSDefaultStyleSheets::ensureMobileViewportStyleSheet() {
+  if (!m_mobileViewportStyleSheet)
     m_mobileViewportStyleSheet =
         parseUASheet(loadResourceAsASCIIString("viewportAndroid.css"));
-    m_defaultMobileViewportStyle->addRulesFromSheet(
-        m_mobileViewportStyleSheet.get(), screenEval());
-  }
-  return m_defaultMobileViewportStyle.get();
+  return m_mobileViewportStyleSheet;
 }
 
-RuleSet* CSSDefaultStyleSheets::defaultTelevisionViewportStyle() {
-  if (!m_defaultTelevisionViewportStyle) {
-    m_defaultTelevisionViewportStyle = RuleSet::create();
+StyleSheetContents*
+CSSDefaultStyleSheets::ensureTelevisionViewportStyleSheet() {
+  if (!m_televisionViewportStyleSheet)
     m_televisionViewportStyleSheet =
         parseUASheet(loadResourceAsASCIIString("viewportTelevision.css"));
-    m_defaultTelevisionViewportStyle->addRulesFromSheet(
-        m_televisionViewportStyleSheet.get(), screenEval());
-  }
-  return m_defaultTelevisionViewportStyle.get();
+  return m_televisionViewportStyleSheet;
 }
 
 void CSSDefaultStyleSheets::ensureDefaultStyleSheetsForElement(
     const Element& element,
     bool& changedDefaultStyle) {
   // FIXME: We should assert that the sheet only styles SVG elements.
   if (element.isSVGElement() && !m_svgStyleSheet) {
     m_svgStyleSheet = parseUASheet(loadResourceAsASCIIString("svg.css"));
     m_defaultStyle->addRulesFromSheet(svgStyleSheet(), screenEval());
     m_defaultPrintStyle->addRulesFromSheet(svgStyleSheet(), printEval());
@@ skipping 35 matching lines @@
 
   String fullscreenRules = loadResourceAsASCIIString("fullscreen.css") +
                            LayoutTheme::theme().extraFullscreenStyleSheet();
   m_fullscreenStyleSheet = parseUASheet(fullscreenRules);
   m_defaultStyle->addRulesFromSheet(fullscreenStyleSheet(), screenEval());
   m_defaultQuirksStyle->addRulesFromSheet(fullscreenStyleSheet(), screenEval());
 }
 
 DEFINE_TRACE(CSSDefaultStyleSheets) {
   visitor->trace(m_defaultStyle);
-  visitor->trace(m_defaultMobileViewportStyle);
-  visitor->trace(m_defaultTelevisionViewportStyle);
   visitor->trace(m_defaultQuirksStyle);
   visitor->trace(m_defaultPrintStyle);
   visitor->trace(m_defaultViewSourceStyle);
-  visitor->trace(m_defaultXHTMLMobileProfileStyle);
   visitor->trace(m_defaultStyleSheet);
   visitor->trace(m_mobileViewportStyleSheet);
   visitor->trace(m_televisionViewportStyleSheet);
+  visitor->trace(m_xhtmlMobileProfileStyleSheet);
   visitor->trace(m_quirksStyleSheet);
   visitor->trace(m_svgStyleSheet);
   visitor->trace(m_mathmlStyleSheet);
   visitor->trace(m_mediaControlsStyleSheet);
   visitor->trace(m_fullscreenStyleSheet);
 }
 
 }  // namespace blink