Add 'dart:debugger' library

runtime/lib/debugger.dart

Index: runtime/lib/debugger.dart
diff --git a/pkg/docgen/test/multi_library_code/lib/test_lib2_foo.dart b/runtime/lib/debugger.dart
similarity index 65%
copy from pkg/docgen/test/multi_library_code/lib/test_lib2_foo.dart
copy to runtime/lib/debugger.dart
index 1b3d037c5bce3add4829e93b527bc5eb7f01f821..66012752438d5eca67b2f7dd89d00d39dcc64f4d 100644
--- a/pkg/docgen/test/multi_library_code/lib/test_lib2_foo.dart
+++ b/runtime/lib/debugger.dart
@@ -2,14 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-library test_lib2_foo;
+import 'dart:_internal';
 
-export 'test_lib2_bar.dart';
-
-class Foo {
-
-}
-
-main() {
-  print('hello world');
+patch class Debugger {
+  /* patch */ static void breakpoint() native "Debugger_breakpoint";

[hausner, 2015/05/05 00:16:26]

Is this name dictated by some spec? I think a verb would make more sense if you
have the liberty to choose. Debugger.suspend() or Debugger.halt() or something
is maybe more descriptive than Debugger.breakpoint().

Unfortunately, Debugger.break() doesn't work because break is a keyword.

There is a bit of bikeshedding about this in dartbug.com/10536

[Cutch, 2015/05/05 02:38:53]

I went with "breakHere" and "breakHereIf".

 }