Merge the dart:uri library into dart:core and update the Uri class

sdk/lib/_internal/compiler/implementation/filenames.dart

Index: sdk/lib/_internal/compiler/implementation/filenames.dart
diff --git a/sdk/lib/_internal/compiler/implementation/filenames.dart b/sdk/lib/_internal/compiler/implementation/filenames.dart
index 46bc421a1cc75abe7d902f19b155915ef3bc0765..c5cc4e9fc34c38306dc4ed8d8100d7862e76970e 100644
--- a/sdk/lib/_internal/compiler/implementation/filenames.dart
+++ b/sdk/lib/_internal/compiler/implementation/filenames.dart
@@ -5,7 +5,6 @@
 library filenames;
 
 import 'dart:io';
-import 'dart:uri';
 
 // TODO(ahe): This library should be replaced by a general
 // path-munging library.
@@ -21,7 +20,7 @@ String uriPathToNative(String path) {
   return new Path(path).toNativePath();
 }
 
-final Uri currentDirectory = new Uri.fromComponents(
+final Uri currentDirectory = new Uri(
     scheme: 'file',
     path: appendSlash(nativeToUriPath(new File('.').fullPathSync())));