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/CIndex.cpp b/tools/libclang/CIndex.cpp
index 2ab693e..8d0f5fa 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -2429,7 +2429,7 @@
   FileSystemOptions FileSystemOpts;
   FileSystemOpts.WorkingDir = CXXIdx->getWorkingDirectory();
 
-  llvm::IntrusiveRefCntPtr<DiagnosticsEngine> Diags;
+  IntrusiveRefCntPtr<DiagnosticsEngine> Diags;
   ASTUnit *TU = ASTUnit::LoadFromASTFile(ast_filename, Diags, FileSystemOpts,
                                   CXXIdx->getOnlyLocalDecls(),
                                   0, 0, true);
@@ -2492,7 +2492,7 @@
   
   // Configure the diagnostics.
   DiagnosticOptions DiagOpts;
-  llvm::IntrusiveRefCntPtr<DiagnosticsEngine>
+  IntrusiveRefCntPtr<DiagnosticsEngine>
     Diags(CompilerInstance::createDiagnostics(DiagOpts, num_command_line_args, 
                                                 command_line_args));