Fix comment alignment behavior.

In the following snippet, clang-format incorrectly aligned the
trailing comment, when only the last line was formatted:

  int aaaaaa; // comment
  int b;
  int c; // Formatting only this line moved this comment.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180173 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Format/WhitespaceManager.h b/lib/Format/WhitespaceManager.h
index 252997f..2833e24 100644
--- a/lib/Format/WhitespaceManager.h
+++ b/lib/Format/WhitespaceManager.h
@@ -66,6 +66,9 @@
 
   void addUntouchableComment(unsigned Column);
 
+  /// \brief Try to align all stashed comments.
+  void alignComments();
+
 private:
   std::string getNewLineText(unsigned NewLines, unsigned Spaces);
 
@@ -84,9 +87,6 @@
   SmallVector<StoredComment, 16> Comments;
   typedef SmallVector<StoredComment, 16>::iterator comment_iterator;
 
-  /// \brief Try to align all stashed comments.
-  void alignComments();
-
   /// \brief Put all the comments between \p I and \p E into \p Column.
   void alignComments(comment_iterator I, comment_iterator E, unsigned Column);