[C++11] Use 'nullptr'. Unittests edition.

llvm-svn: 210423
diff --git a/clang/unittests/Lex/PPCallbacksTest.cpp b/clang/unittests/Lex/PPCallbacksTest.cpp
index cceebea..5ca2013 100644
--- a/clang/unittests/Lex/PPCallbacksTest.cpp
+++ b/clang/unittests/Lex/PPCallbacksTest.cpp
@@ -48,7 +48,7 @@
                          bool Complain) override { }
 
   GlobalModuleIndex *loadGlobalModuleIndex(SourceLocation TriggerLoc) override
-    { return 0; }
+    { return nullptr; }
   bool lookupMissingImports(StringRef Name, SourceLocation TriggerLoc) override
     { return 0; };
 };
@@ -174,7 +174,7 @@
 
     IntrusiveRefCntPtr<PreprocessorOptions> PPOpts = new PreprocessorOptions();
     Preprocessor PP(PPOpts, Diags, LangOpts, SourceMgr, HeaderInfo, ModLoader,
-                    /*IILookup =*/0,
+                    /*IILookup =*/nullptr,
                     /*OwnsHeaderSearch =*/false);
     PP.Initialize(*Target);
     InclusionDirectiveCallbacks* Callbacks = new InclusionDirectiveCallbacks;
@@ -207,7 +207,7 @@
                             OpenCLLangOpts, Target.getPtr());
 
     Preprocessor PP(new PreprocessorOptions(), Diags, OpenCLLangOpts, SourceMgr,
-                    HeaderInfo, ModLoader, /*IILookup =*/0,
+                    HeaderInfo, ModLoader, /*IILookup =*/nullptr,
                     /*OwnsHeaderSearch =*/false);
     PP.Initialize(*Target);