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 9eaf555e5f11781fda7cdec86be75e18f6bb4642..2b02b718905f82edc4dbb15f83860e23e8c5c975 100644
--- a/Source/core/dom/ViewportArguments.h
+++ b/Source/core/dom/ViewportArguments.h
@@ -50,13 +50,11 @@ struct ViewportArguments {
 
     enum Type {
         // These are ordered in increasing importance.
-        Implicit,
-        XHTMLMobileProfile,
+        UserAgentStyleSheet,
         HandheldFriendlyMeta,
         MobileOptimizedMeta,
         ViewportMeta,
-        ViewportMetaLayoutSizeQuirk,
-        CSSDeviceAdaptation
+        AuthorStyleSheet
     } type;
 
     enum {
@@ -72,10 +70,8 @@ struct ViewportArguments {
         ValueExtendToZoom = -10
     };
 
-    ViewportArguments(Type type = Implicit)
+    ViewportArguments(Type type = UserAgentStyleSheet)
         : type(type)
-        , width(ValueAuto)
-        , height(ValueAuto)
         , zoom(ValueAuto)
         , minZoom(ValueAuto)
         , maxZoom(ValueAuto)
@@ -86,12 +82,10 @@ struct ViewportArguments {
     }
 
     // All arguments are in CSS units.
-    PageScaleConstraints resolve(const FloatSize& initialViewportSize, int defaultWidth) const;
+    PageScaleConstraints resolve(const FloatSize& initialViewportSize) const;
 
-    float width;
     Length minWidth;
     Length maxWidth;
-    float height;
     Length minHeight;
     Length maxHeight;
     float zoom;
@@ -105,10 +99,8 @@ struct ViewportArguments {
     {
         // 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
+        return minWidth == other.minWidth
             && maxWidth == other.maxWidth
-            && height == other.height
             && minHeight == other.minHeight
             && maxHeight == other.maxHeight
             && zoom == other.zoom
@@ -124,6 +116,8 @@ struct ViewportArguments {
         return !(*this == other);
     }
 
+    bool isLegacyViewportType() const { return type >= HandheldFriendlyMeta && type <= ViewportMeta; }
+
 private:
     enum Direction { Horizontal, Vertical };
     static float resolveViewportLength(const Length&, const FloatSize& initialViewportSize, Direction);