allow asset root urls to be configurable

src/Illuminate/Routing/RoutingServiceProvider.php

@@ -59,7 +59,7 @@ protected function registerUrlGenerator()
             $url = new UrlGenerator(
                 $routes, $app->rebinding(
                     'request', $this->requestRebinder()
-                )
+                ), $app['config']['app.asset_url']
             );
 
             // Next we will set a few service resolvers on the URL generator so it can

src/Illuminate/Routing/UrlGenerator.php

@@ -31,6 +31,13 @@ class UrlGenerator implements UrlGeneratorContract
      */
     protected $request;
 
+    /**
+     * The asset root URL.
+     *
+     * @var string
+     */
+    protected $assetRoot;
+
     /**
      * The forced URL root.
      *
@@ -106,11 +113,13 @@ class UrlGenerator implements UrlGeneratorContract
      *
      * @param  \Illuminate\Routing\RouteCollection  $routes
      * @param  \Illuminate\Http\Request  $request
+     * @param  string  $assetRoot
      * @return void
      */
-    public function __construct(RouteCollection $routes, Request $request)
+    public function __construct(RouteCollection $routes, Request $request, $assetRoot = null)
     {
         $this->routes = $routes;
+        $this->assetRoot = $assetRoot;
 
         $this->setRequest($request);
     }
@@ -229,7 +238,9 @@ public function asset($path, $secure = null)
         // Once we get the root URL, we will check to see if it contains an index.php
         // file in the paths. If it does, we will remove it since it is not needed
         // for asset paths, but only for routes to endpoints in the application.
-        $root = $this->formatRoot($this->formatScheme($secure));
+        $root = $this->assetRoot
+                    ? $this->assetRoot
+                    : $this->formatRoot($this->formatScheme($secure));
 
         return $this->removeIndex($root).'/'.trim($path, '/');
     }