Add --set-exit-code-on-problem option.

pkg/front_end/lib/src/fasta/compiler_command_line.dart

Index: pkg/front_end/lib/src/fasta/compiler_command_line.dart
diff --git a/pkg/front_end/lib/src/fasta/compiler_command_line.dart b/pkg/front_end/lib/src/fasta/compiler_command_line.dart
index 885f01f218f778045b6480d955a3b62efb2f4f5c..04a4b6c68ae8aee16f616cdd3aff285a5b3190ff 100644
--- a/pkg/front_end/lib/src/fasta/compiler_command_line.dart
+++ b/pkg/front_end/lib/src/fasta/compiler_command_line.dart
@@ -54,6 +54,10 @@ class CompilerCommandLine extends CommandLine {
         options.containsKey("/?");
   }
 
+  bool get setExitCodeOnProblem {
+    return options.containsKey("--set-exit-code-on-problem");
+  }
+
   void validate() {
     if (help) {
       print(computeUsage(programName, verbose));