Use css-device-adapt constraining for legacy viewport tags.

Source/core/dom/ViewportArguments.h

Index: Source/core/dom/ViewportArguments.h
diff --git a/Source/core/dom/ViewportArguments.h b/Source/core/dom/ViewportArguments.h
index ea9a44e60a3897fc7dea694aa2383cfdc953ff9b..5afe513b9dfd513630a4cc4c5781a25266152f02 100644
--- a/Source/core/dom/ViewportArguments.h
+++ b/Source/core/dom/ViewportArguments.h
@@ -49,13 +49,11 @@ struct ViewportArguments {
 
     enum Type {
         // These are ordered in increasing importance.
-        Implicit,
-        XHTMLMobileProfile,
+        UserAgentStyleSheet,
         HandheldFriendlyMeta,
         MobileOptimizedMeta,
         ViewportMeta,
-        ViewportMetaLayoutSizeQuirk,
-        CSSDeviceAdaptation
+        AuthorStyleSheet
     } type;
 
     enum {
@@ -71,12 +69,10 @@ struct ViewportArguments {
         ValueExtendToZoom = -10
     };
 
-    ViewportArguments(Type type = Implicit)
+    ViewportArguments(Type type = UserAgentStyleSheet)
         : type(type)
-        , width(ValueAuto)
         , minWidth(ValueAuto)
         , maxWidth(ValueAuto)
-        , height(ValueAuto)
         , minHeight(ValueAuto)
         , maxHeight(ValueAuto)
         , zoom(ValueAuto)
@@ -89,12 +85,10 @@ struct ViewportArguments {
     }
 
     // All arguments are in CSS units.
-    PageScaleConstraints resolve(const FloatSize& initialViewportSize, int defaultWidth) const;
+    PageScaleConstraints resolve(const FloatSize& initialViewportSize) const;
 
-    float width;
     float minWidth;
     float maxWidth;
-    float height;
     float minHeight;
     float maxHeight;
     float zoom;
@@ -106,12 +100,9 @@ struct ViewportArguments {
 
     bool operator==(const ViewportArguments& other) const
     {
-        // Used for figuring out whether to reset the viewport or not,
-        // thus we are not taking type into account.
-        return width == other.width
-            && minWidth == other.minWidth
+        // Used for figuring out whether to reset the viewport or not.
+        return minWidth == other.minWidth
             && maxWidth == other.maxWidth
-            && height == other.height
             && minHeight == other.minHeight
             && maxHeight == other.maxHeight
             && zoom == other.zoom