Introduce ASTUnresolvedSet, an UnresolvedSet-like class, whose contents are
allocated using the allocator associated with an ASTContext.

Use this inside CXXRecordDecl::DefinitionData instead of an UnresolvedSet to
avoid a potential memory leak.

rdar://12761275

llvm-svn: 168771
diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
index 367f75f..529cfea 100644
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1868,7 +1868,7 @@
       break;
 
     case EXPR_INIT_LIST:
-      S = new (Context) InitListExpr(getContext(), Empty);
+      S = new (Context) InitListExpr(Empty);
       break;
 
     case EXPR_DESIGNATED_INIT: