Implement support for the binary operator '%' in the translator.

BUG=angle:854

Change-Id: If116de132dc83d93255749b54c1919a75abcb65c
Reviewed-on: https://chromium-review.googlesource.com/236330
Tested-by: Gregoire Payen de La Garanderie <Gregory.Payen@imgtec.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/translator/ValidateLimitations.cpp b/src/compiler/translator/ValidateLimitations.cpp
index 896e1cd..c4dad54 100644
--- a/src/compiler/translator/ValidateLimitations.cpp
+++ b/src/compiler/translator/ValidateLimitations.cpp
@@ -56,6 +56,7 @@
       case EOpAddAssign: return "+=";
       case EOpSubAssign: return "-=";
       case EOpDivAssign: return "/=";
+      case EOpModAssign: return "%=";
 
       // Fall-through.
       case EOpMulAssign:
@@ -75,7 +76,7 @@
       case EOpSub: return "-";
       case EOpMul: return "*";
       case EOpDiv: return "/";
-      case EOpMod: UNIMPLEMENTED(); break;
+      case EOpMod: return "%";
       case EOpEqual: return "==";
       case EOpNotEqual: return "!=";
       case EOpLessThan: return "<";