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/ShaderLang.cpp b/src/compiler/translator/ShaderLang.cpp
index 9ac335a..831f369 100644
--- a/src/compiler/translator/ShaderLang.cpp
+++ b/src/compiler/translator/ShaderLang.cpp
@@ -71,14 +71,14 @@
 {
     if (!handle)
     {
-        return NULL;
+        return nullptr;
     }
 
     TShHandleBase *base = static_cast<TShHandleBase *>(handle);
     TCompiler *compiler = base->getAsCompiler();
     if (!compiler)
     {
-        return NULL;
+        return nullptr;
     }
 
     return GetVariableList<VarT>(compiler);
@@ -87,7 +87,7 @@
 TCompiler *GetCompilerFromHandle(ShHandle handle)
 {
     if (!handle)
-        return NULL;
+        return nullptr;
     TShHandleBase *base = static_cast<TShHandleBase *>(handle);
     return base->getAsCompiler();
 }
@@ -96,7 +96,7 @@
 TranslatorHLSL *GetTranslatorHLSLFromHandle(ShHandle handle)
 {
     if (!handle)
-        return NULL;
+        return nullptr;
     TShHandleBase *base = static_cast<TShHandleBase *>(handle);
     return base->getAsTranslatorHLSL();
 }