Add some typedefs for clarity.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164223 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/CXXInheritance.h b/include/clang/AST/CXXInheritance.h
index ee6eba7..5e3145f 100644
--- a/include/clang/AST/CXXInheritance.h
+++ b/include/clang/AST/CXXInheritance.h
@@ -271,15 +271,14 @@
 /// pair is the virtual method that overrides it (including the
 /// subobject in which that virtual function occurs).
 class OverridingMethods {
-  llvm::DenseMap<unsigned, SmallVector<UniqueVirtualMethod, 4> > 
-    Overrides;
+  typedef SmallVector<UniqueVirtualMethod, 4> ValuesT;
+  typedef llvm::DenseMap<unsigned, ValuesT> MapType;
+  MapType Overrides;
 
 public:
   // Iterate over the set of subobjects that have overriding methods.
-  typedef llvm::DenseMap<unsigned, SmallVector<UniqueVirtualMethod, 4> >
-            ::iterator iterator;
-  typedef llvm::DenseMap<unsigned, SmallVector<UniqueVirtualMethod, 4> >
-            ::const_iterator const_iterator;
+  typedef MapType::iterator iterator;
+  typedef MapType::const_iterator const_iterator;
   iterator begin() { return Overrides.begin(); }
   const_iterator begin() const { return Overrides.begin(); }
   iterator end() { return Overrides.end(); }