Moved remaining legacy viewport tests to unit tests.

Source/web/tests/FrameTestHelpers.h

Index: Source/web/tests/FrameTestHelpers.h
diff --git a/Source/web/tests/FrameTestHelpers.h b/Source/web/tests/FrameTestHelpers.h
index 9fc9dfc06a2fd6f5a58b937efe658cbdbbe68293..7dc714d1dd5450e567c57732c2be71f56cb4ced9 100644
--- a/Source/web/tests/FrameTestHelpers.h
+++ b/Source/web/tests/FrameTestHelpers.h
@@ -46,6 +46,7 @@ namespace FrameTestHelpers {
 
 void loadFrame(WebFrame*, const std::string& url);
 void runPendingTasks();
+void setViewportSettings(WebSettings*);
 
 // Convenience class for handling the lifetime of a WebView and its associated mainframe in tests.
 class WebViewHelper {
@@ -72,6 +73,23 @@ private:
     WebViewImpl* m_webView;
 };
 
+class UseMockScrollbarSettings {
+public:
+    UseMockScrollbarSettings();
+    ~UseMockScrollbarSettings();
+};
+
+class ReplaceViewportUAStylesheet {
+public:
+    ReplaceViewportUAStylesheet(WTF::String);
+    ~ReplaceViewportUAStylesheet();
+};
+
+class UseAndroidViewportUAStylesheet : public ReplaceViewportUAStylesheet {
+public:
+    UseAndroidViewportUAStylesheet();
+};
+
 } // namespace FrameTestHelpers
 } // namespace blink