Add some side-effect free Create methods for TypeDecl subclasses and use them for PCH reading.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107468 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index 9ab44b6..a77c1c8 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -58,6 +58,11 @@
   return R;
 }
 
+CXXRecordDecl *CXXRecordDecl::Create(ASTContext &C, EmptyShell Empty) {
+  return new (C) CXXRecordDecl(CXXRecord, TTK_Struct, 0, SourceLocation(), 0, 0,
+                               SourceLocation());
+}
+
 CXXRecordDecl::~CXXRecordDecl() {
 }