Use the SelectorSet typedef more widely throughout Sema.

While there make it a SmallPtrSet.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@157532 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaObjCProperty.cpp b/lib/Sema/SemaObjCProperty.cpp
index 222eaac..88de7d3 100644
--- a/lib/Sema/SemaObjCProperty.cpp
+++ b/lib/Sema/SemaObjCProperty.cpp
@@ -1523,7 +1523,7 @@
 
 void Sema::DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
                                       ObjCContainerDecl *CDecl,
-                                      const llvm::DenseSet<Selector>& InsMap) {
+                                      const SelectorSet &InsMap) {
   llvm::DenseMap<IdentifierInfo *, ObjCPropertyDecl*> SuperPropMap;
   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(CDecl))
     CollectSuperClassPropertyImplementations(IDecl, SuperPropMap);