Use Rewriter::overwriteChangedFiles() directly

This replaces the custom code in RefactoringTool::saveRewrittenFiles() which
lacked atomic file saving and error diagnostics, resolving an old FIXME from
r157331.

Landing this time with the proper return code, plus a very unhelpful comment
cleared up.

Rubber-stamped by Manuel Klimek.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193594 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Tooling/Refactoring.cpp b/lib/Tooling/Refactoring.cpp
index 9e58db0..e165c12 100644
--- a/lib/Tooling/Refactoring.cpp
+++ b/lib/Tooling/Refactoring.cpp
@@ -301,23 +301,7 @@
 }
 
 int RefactoringTool::saveRewrittenFiles(Rewriter &Rewrite) {
-  for (Rewriter::buffer_iterator I = Rewrite.buffer_begin(),
-                                 E = Rewrite.buffer_end();
-       I != E; ++I) {
-    // FIXME: This code is copied from the FixItRewriter.cpp - I think it should
-    // go into directly into Rewriter (there we also have the Diagnostics to
-    // handle the error cases better).
-    const FileEntry *Entry =
-        Rewrite.getSourceMgr().getFileEntryForID(I->first);
-    std::string ErrorInfo;
-    llvm::raw_fd_ostream FileStream(Entry->getName(), ErrorInfo,
-                                    llvm::sys::fs::F_Binary);
-    if (!ErrorInfo.empty())
-      return 1;
-    I->second.write(FileStream);
-    FileStream.flush();
-  }
-  return 0;
+  return Rewrite.overwriteChangedFiles() ? 1 : 0;
 }
 
 } // end namespace tooling