Error when encountering non-preprocessor tokens before #extension in ESSL3.

BUG=angleproject:1047

Change-Id: I4a548270f651e35b2c8d1ab5d0f46185230c5f74
Reviewed-on: https://chromium-review.googlesource.com/281216
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/compiler/preprocessor/DiagnosticsBase.cpp b/src/compiler/preprocessor/DiagnosticsBase.cpp
index 5a1c390..c74c42c 100644
--- a/src/compiler/preprocessor/DiagnosticsBase.cpp
+++ b/src/compiler/preprocessor/DiagnosticsBase.cpp
@@ -117,6 +117,8 @@
         return "invalid pragma";
       case PP_INVALID_PRAGMA_VALUE:
         return "invalid pragma value, must be 'on' or 'off'";
+      case PP_NON_PP_TOKEN_BEFORE_EXTENSION_ESSL3:
+        return "extension directive must occur before any non-preprocessor tokens in ESSL3";
       // Errors end.
       // Warnings begin.
       case PP_EOF_IN_DIRECTIVE:
@@ -125,8 +127,8 @@
         return "unexpected token after conditional expression";
       case PP_UNRECOGNIZED_PRAGMA:
         return "unrecognized pragma";
-      case PP_NON_PP_TOKEN_BEFORE_EXTENSION:
-        return "extension directive must occur before any non-preprocessor tokens";
+      case PP_NON_PP_TOKEN_BEFORE_EXTENSION_ESSL1:
+        return "extension directive should occur before any non-preprocessor tokens";
       // Warnings end.
       default:
         assert(false);