Refactoring: replace NULL by nullptr for pointers (3rd CL).

This CL mainly handles passing/returning NULL to/from a function.

BUG=angleproject:2001

Change-Id: I34802f792e710e3d7ff697cbe4701dc1bf5ab009
Reviewed-on: https://chromium-review.googlesource.com/485060
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/translator/StructureHLSL.cpp b/src/compiler/translator/StructureHLSL.cpp
index fd140ae..57c7c75 100644
--- a/src/compiler/translator/StructureHLSL.cpp
+++ b/src/compiler/translator/StructureHLSL.cpp
@@ -163,13 +163,13 @@
     }
     else
     {
-        return define(structure, useHLSLRowMajorPacking, useStd140Packing, NULL);
+        return define(structure, useHLSLRowMajorPacking, useStd140Packing, nullptr);
     }
 }
 
 TString StructureHLSL::defineNameless(const TStructure &structure)
 {
-    return define(structure, false, false, NULL);
+    return define(structure, false, false, nullptr);
 }
 
 TString StructureHLSL::define(const TStructure &structure,