Add HttpRequest::requestedUri.

sdk/lib/io/http_impl.dart

Index: sdk/lib/io/http_impl.dart
diff --git a/sdk/lib/io/http_impl.dart b/sdk/lib/io/http_impl.dart
index ca47bd85db6a35f0d697fe7100153740040539bd..09e03c87a99b43ab9c51c62d7bf2dde746e9516c 100644
--- a/sdk/lib/io/http_impl.dart
+++ b/sdk/lib/io/http_impl.dart
@@ -90,6 +90,8 @@ class _HttpRequest extends _HttpInboundMessage implements HttpRequest {
 
   _HttpSession _session;
 
+  Uri _requestedUri;
+
   _HttpRequest(_HttpResponse this.response,
                _HttpIncoming _incoming,
                _HttpServer this._httpServer,
@@ -127,6 +129,27 @@ class _HttpRequest extends _HttpInboundMessage implements HttpRequest {
 
   Uri get uri => _incoming.uri;
 
+  Uri get requestedUri {
+    if (_requestedUri == null) {
+      var proto = headers['x-forwarded-proto'];
+      var scheme = proto != null ? proto.first :
+          _httpConnection._socket is SecureSocket ? "https" : "http";
+      var host = headers['x-forwarded-host'];
+      if (host != null) {
+        host = host.first;
+      } else {
+        host = headers['host'];
+        if (host != null) {
+          host = host.first;
+        } else {
+          host = "${_httpServer.address.host}:${_httpServer.port}";
+        }
+      }
+      _requestedUri = Uri.parse("$scheme://$host$uri");
+    }
+    return _requestedUri;
+  }
+
   String get method => _incoming.method;
 
   HttpSession get session {