[C++11] Replacing DeclBase iterators decls_begin() and decls_end() with iterator_range decls(). The same is true for the noload versions of these APIs. Updating all of the usages of the iterators with range-based for loops.

llvm-svn: 203278
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index ace3e9c..a3ebd41 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -873,9 +873,8 @@
   void handleFileLevelDecl(Decl *D) {
     Unit.addFileLevelDecl(D);
     if (NamespaceDecl *NSD = dyn_cast<NamespaceDecl>(D)) {
-      for (NamespaceDecl::decl_iterator
-             I = NSD->decls_begin(), E = NSD->decls_end(); I != E; ++I)
-        handleFileLevelDecl(*I);
+      for (auto *I : NSD->decls())
+        handleFileLevelDecl(I);
     }
   }