Unify AssertionError.

corelib/src/exceptions.dart

Index: corelib/src/exceptions.dart
diff --git a/corelib/src/exceptions.dart b/corelib/src/exceptions.dart
index 2c72deea8e42a098010da46227bea17c09b0ad8f..b1546bbede3d70e134daba475ac332092ddb4f44 100644
--- a/corelib/src/exceptions.dart
+++ b/corelib/src/exceptions.dart
@@ -194,3 +194,6 @@ class IntegerDivisionByZeroException implements Exception {
   const IntegerDivisionByZeroException();
   String toString() => "IntegerDivisionByZeroException";
 }
+
+class AssertionError {

[Anders Johnsen, 2012/08/27 12:18:44]

Should we create a private constructor so it's not externally constructable?
Note that this is a part of 'dart:core' - I don't know if we normally do that
here.

[Mads Ager (google), 2012/08/28 13:01:37]

If we put it in here we should probably call it AssertionException and make it
implement Exception?

[Mads Ager (google), 2012/08/28 13:01:37]

I don't think there is any harm in this being instantiable by the user.

[Anders Johnsen, 2012/08/28 14:39:18]

Sorry, didn't see that comment earlier on. I've created an errors.dart file in
corelib/src/, since these are indeed errors (defined in the spec as such).

+}