preprocessor: Fix use after free when #undef the macro being invoked

BUG=chromium:648031
BUG=angleproject:1522

Change-Id: I825cea9e736a2c99133408249cfcd525431d31de
Reviewed-on: https://chromium-review.googlesource.com/386853
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/compiler/preprocessor/DiagnosticsBase.h b/src/compiler/preprocessor/DiagnosticsBase.h
index a089920..6c3fe9e 100644
--- a/src/compiler/preprocessor/DiagnosticsBase.h
+++ b/src/compiler/preprocessor/DiagnosticsBase.h
@@ -44,6 +44,7 @@
         PP_MACRO_PREDEFINED_REDEFINED,
         PP_MACRO_PREDEFINED_UNDEFINED,
         PP_MACRO_UNTERMINATED_INVOCATION,
+        PP_MACRO_UNDEFINED_WHILE_INVOKED,
         PP_MACRO_TOO_FEW_ARGS,
         PP_MACRO_TOO_MANY_ARGS,
         PP_MACRO_DUPLICATE_PARAMETER_NAMES,