First step towards having patch files for generic libraries.

tests/compiler/dart2js/mock_compiler.dart

Index: tests/compiler/dart2js/mock_compiler.dart
diff --git a/tests/compiler/dart2js/mock_compiler.dart b/tests/compiler/dart2js/mock_compiler.dart
index 5719f01839f8d2243808af307787dabd3ab14bf1..0301ea1dc23edc7b22b4b76d22b01ac5aa5c6c7d 100644
--- a/tests/compiler/dart2js/mock_compiler.dart
+++ b/tests/compiler/dart2js/mock_compiler.dart
@@ -156,6 +156,9 @@ class MockCompiler extends Compiler {
     // Do nothing. The mock core library is already handled in the constructor.
   }
 
+  // The mock library don't need any patches.

[floitsch, 2012/06/29 12:11:51]

doesn't

[Lasse Reichstein Nielsen, 2012/06/29 12:19:35]

Done.

+  Uri resolvePatchUri(String dartLibraryName) => null;
+
   Script readScript(Uri uri, [ScriptTag node]) {
     String code = sources[uri.toString()];
     if (code === null) throw new IllegalArgumentException(uri);