Basic: import IntrusiveRefCntPtr<> into clang namespace

The class name is long enough without the llvm:: added.
Also bring in RefCountedBase and RefCountedBaseVPTR.

llvm-svn: 150958
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 1f56a2f..28043d1 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -73,8 +73,8 @@
                      const LangOptions &LangOpts, const TargetInfo *Target)
   : LangOpts(LangOpts), Target(Target), BuiltinIncludeDir(0)
 {
-  llvm::IntrusiveRefCntPtr<DiagnosticIDs> DiagIDs(new DiagnosticIDs);
-  Diags = llvm::IntrusiveRefCntPtr<DiagnosticsEngine>(
+  IntrusiveRefCntPtr<DiagnosticIDs> DiagIDs(new DiagnosticIDs);
+  Diags = IntrusiveRefCntPtr<DiagnosticsEngine>(
             new DiagnosticsEngine(DiagIDs));
   Diags->setClient(DC.clone(*Diags), /*ShouldOwnClient=*/true);
   SourceMgr = new SourceManager(*Diags, FileMgr);