Teach window.location.href setter to handle relative urls.

sky/engine/core/frame/LocalDOMWindow.cpp

Index: sky/engine/core/frame/LocalDOMWindow.cpp
diff --git a/sky/engine/core/frame/LocalDOMWindow.cpp b/sky/engine/core/frame/LocalDOMWindow.cpp
index 0342914477609820b17e2d41aad3e46793752f5b..16e1da3ced33563888d3423216537dc12a9bfb3d 100644
--- a/sky/engine/core/frame/LocalDOMWindow.cpp
+++ b/sky/engine/core/frame/LocalDOMWindow.cpp
@@ -703,7 +703,7 @@ void LocalDOMWindow::setLocation(const String& urlString, SetLocationLocking loc
     if (!host)
         return;
     mojo::URLRequestPtr request = mojo::URLRequest::New();
-    request->url = urlString.toUTF8();
+    request->url = document()->completeURL(urlString).string().toUTF8();
     host->services()->NavigatorHost()->RequestNavigate(
         mojo::TARGET_SOURCE_NODE, request.Pass());
 }