Create a new expression class, CXXThisExpr, to handle the C++ 'this' primary expression. Remove CXXThis from PredefinedExpr

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@58695 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/StmtPrinter.cpp b/lib/AST/StmtPrinter.cpp
index 51f4f51..34aefc2 100644
--- a/lib/AST/StmtPrinter.cpp
+++ b/lib/AST/StmtPrinter.cpp
@@ -839,6 +839,10 @@
   OS << (Node->getValue() ? "true" : "false");
 }
 
+void StmtPrinter::VisitCXXThisExpr(CXXThisExpr *Node) {
+  OS << "this";
+}
+
 void StmtPrinter::VisitCXXThrowExpr(CXXThrowExpr *Node) {
   if (Node->getSubExpr() == 0)
     OS << "throw";