Fixing stack traces on IE10.

BUG=
R=nweiz@google.com

Review URL: https://codereview.chromium.org//23445005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/stack_trace@26735 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/pkgs/stack_trace/lib/src/trace.dart b/pkgs/stack_trace/lib/src/trace.dart
index 19f0a12..bf14ee2 100644
--- a/pkgs/stack_trace/lib/src/trace.dart
+++ b/pkgs/stack_trace/lib/src/trace.dart
@@ -19,8 +19,14 @@
 /// V8's traces start with a line that's either just "Error" or else is a
 /// description of the exception that occurred. That description can be multiple
 /// lines, so we just look for any line other than the first that begins with
-/// four spaces and "at".
-final _v8Trace = new RegExp(r"\n    at ");
+/// three or four spaces and "at".
+final _v8Trace = new RegExp(r"\n    ?at ");
+
+/// A RegExp to match indidual lines of V8's stack traces.
+///
+/// This is intended to filter out the leading exception details of the trace
+/// though it is possible for the message to match this as well.
+final _v8TraceLine = new RegExp(r"    ?at ");
 
 /// A RegExp to match Firefox's stack traces.
 ///
@@ -106,7 +112,7 @@
           // It's possible that an Exception's description contains a line that
           // looks like a V8 trace line, which will screw this up.
           // Unfortunately, that's impossible to detect.
-          .skipWhile((line) => !line.startsWith("    at "))
+          .skipWhile((line) => !line.startsWith(_v8TraceLine))
           .map((line) => new Frame.parseV8(line)));
 
   /// Parses a string representation of an Internet Explorer stack trace.