Add a client_id field to CrashReport (#22) r=mmentovai.

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@23 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/google/crash_report.h

@@ -34,6 +34,9 @@ struct CrashReport {
   // and is not used by airbag.
   string report_id;
 
+  // An optional id which identifies the client that generated the report.
+  string client_id;
+
   // The time that the report was uploaded (milliseconds since the epoch)
   airbag_time_t report_time;