Fix include guards.

BUG=angle:733

Change-Id: I08b2c11c4831f1161c178c1842b10e807185aced
Reviewed-on: https://chromium-review.googlesource.com/230831
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/compiler/translator/ValidateLimitations.h b/src/compiler/translator/ValidateLimitations.h
index e6e8a96..59cccb5 100644
--- a/src/compiler/translator/ValidateLimitations.h
+++ b/src/compiler/translator/ValidateLimitations.h
@@ -4,6 +4,9 @@
 // found in the LICENSE file.
 //
 
+#ifndef COMPILER_TRANSLATOR_VALIDATELIMITATIONS_H_
+#define COMPILER_TRANSLATOR_VALIDATELIMITATIONS_H_
+
 #include "compiler/translator/IntermNode.h"
 #include "compiler/translator/LoopInfo.h"
 
@@ -53,3 +56,4 @@
     TLoopStack mLoopStack;
 };
 
+#endif // COMPILER_TRANSLATOR_VALIDATELIMITATIONS_H_