Basic: import IntrusiveRefCntPtr<> into clang namespace

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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150958 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/Indexing.cpp b/tools/libclang/Indexing.cpp
index d1af388..69ddc42 100644
--- a/tools/libclang/Indexing.cpp
+++ b/tools/libclang/Indexing.cpp
@@ -279,7 +279,7 @@
 
   // Configure the diagnostics.
   DiagnosticOptions DiagOpts;
-  llvm::IntrusiveRefCntPtr<DiagnosticsEngine>
+  IntrusiveRefCntPtr<DiagnosticsEngine>
     Diags(CompilerInstance::createDiagnostics(DiagOpts, num_command_line_args, 
                                                 command_line_args,
                                                 CaptureDiag,
@@ -309,7 +309,7 @@
   if (source_filename)
     Args->push_back(source_filename);
   
-  llvm::IntrusiveRefCntPtr<CompilerInvocation>
+  IntrusiveRefCntPtr<CompilerInvocation>
     CInvok(createInvocationFromCommandLine(*Args, Diags));
 
   if (!CInvok)