Moved remaining legacy viewport tests to unit tests.

Source/core/css/ViewportStyle.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 10 matching lines @@
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef ViewportStyle_h
 #define ViewportStyle_h
 
 #include "wtf/text/WTFString.h"
 
+namespace blink {
+namespace FrameTestHelpers {
+class ReplaceViewportUAStylesheet;
+}
+}
+
 namespace WebCore {
 
 class ViewportStyle {
 public:
-    static String viewportStyleSheet();
+    static String viewportStyleSheet()
+    {
+        if (!styleOverrideString().isEmpty())
+            return styleOverrideString();
+
+        return platformStyleSheet();
+    }
+
+private:
+    // Implemented in platform-dependent files to return the viewport style to
+    // use on specific platforms.
+    static String platformStyleSheet();
+
+    // Allows tests to override the platform specific stylesheet
+    friend class blink::FrameTestHelpers::ReplaceViewportUAStylesheet;
+    static String& styleOverrideString()
+    {
+        static String &styleString = *new String();
+        return styleString;
+    }
 };
 
 } // namespace WebCore
 
 #endif // ViewportStyle_h