Move code from StyleResolver to ViewportStyleResolver.

Source/core/css/CSSDefaultStyleSheets.cpp

Index: Source/core/css/CSSDefaultStyleSheets.cpp
diff --git a/Source/core/css/CSSDefaultStyleSheets.cpp b/Source/core/css/CSSDefaultStyleSheets.cpp
index 03883ec00d0f8cbeb918ff3d77191949bb60a228..61be83f5453a6c2bae7ccc61ece6cd0f37025e88 100644
--- a/Source/core/css/CSSDefaultStyleSheets.cpp
+++ b/Source/core/css/CSSDefaultStyleSheets.cpp
@@ -75,6 +75,7 @@ static PassRefPtrWillBeRawPtr<StyleSheetContents> parseUASheet(const String& str
 CSSDefaultStyleSheets::CSSDefaultStyleSheets()
     : m_defaultStyle(nullptr)
     , m_defaultViewportStyle(nullptr)
+    , m_defaultViewportOverrideStyle(nullptr)
     , m_defaultQuirksStyle(nullptr)
     , m_defaultPrintStyle(nullptr)
     , m_defaultViewSourceStyle(nullptr)
@@ -82,6 +83,7 @@ CSSDefaultStyleSheets::CSSDefaultStyleSheets()
     , m_defaultTransitionStyle(nullptr)
     , m_defaultStyleSheet(nullptr)
     , m_viewportStyleSheet(nullptr)
+    , m_viewportOverrideStyleSheet(nullptr)
     , m_quirksStyleSheet(nullptr)
     , m_svgStyleSheet(nullptr)
     , m_mathmlStyleSheet(nullptr)
@@ -90,6 +92,7 @@ CSSDefaultStyleSheets::CSSDefaultStyleSheets()
 {
     m_defaultStyle = RuleSet::create();
     m_defaultViewportStyle = RuleSet::create();
+    m_defaultViewportOverrideStyle = RuleSet::create();
     m_defaultPrintStyle = RuleSet::create();
     m_defaultQuirksStyle = RuleSet::create();
 
@@ -97,14 +100,18 @@ CSSDefaultStyleSheets::CSSDefaultStyleSheets()
     String defaultRules = loadResourceAsASCIIString("html.css") + LayoutTheme::theme().extraDefaultStyleSheet();
     m_defaultStyleSheet = parseUASheet(defaultRules);
     m_defaultStyle->addRulesFromSheet(defaultStyleSheet(), screenEval());
+    m_defaultPrintStyle->addRulesFromSheet(defaultStyleSheet(), printEval());
+
+    // @viewport rules.
+    String viewportAndroidRules = loadResourceAsASCIIString("viewportAndroid.css");
+    m_viewportOverrideStyleSheet = parseUASheet(viewportAndroidRules);
 #if OS(ANDROID)
-    String viewportRules = loadResourceAsASCIIString("viewportAndroid.css");
+    m_viewportStyleSheet = m_viewportOverrideStyleSheet;
 #else
-    String viewportRules;
+    m_viewportStyleSheet = parseUASheet(String());
 #endif
-    m_viewportStyleSheet = parseUASheet(viewportRules);
     m_defaultViewportStyle->addRulesFromSheet(viewportStyleSheet(), screenEval());
-    m_defaultPrintStyle->addRulesFromSheet(defaultStyleSheet(), printEval());
+    m_defaultViewportOverrideStyle->addRulesFromSheet(viewportOverrideStyleSheet(), screenEval());
 
     // Quirks-mode rules.
     String quirksRules = loadResourceAsASCIIString("quirks.css") + LayoutTheme::theme().extraQuirksStyleSheet();