Sort "deps" and "public_deps" when running the "gn format" command.

tools/gn/parse_tree.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_GN_PARSE_TREE_H_
 #define TOOLS_GN_PARSE_TREE_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 354 matching lines @@
   void set_begin_token(const Token& t) { begin_token_ = t; }
   void set_end(scoped_ptr<EndNode> e) { end_ = e.Pass(); }
   const EndNode* End() const { return end_.get(); }
 
   void append_item(scoped_ptr<ParseNode> s) {
     contents_.push_back(s.release());
   }
   const std::vector<const ParseNode*>& contents() const { return contents_; }
 
   void SortAsStringsList();
+  void SortAsDepsList();
 
   // During formatting, do we want this list to always be multliline? This is
   // used to make assignments to deps, sources, etc. always be multiline lists,
   // rather than collapsed to a single line when they're one element.
   bool prefer_multiline() const { return prefer_multiline_; }
   void set_prefer_multiline(bool prefer_multiline) {
     prefer_multiline_ = prefer_multiline;
   }
 
   struct SortRange {
     size_t begin;
     size_t end;
     SortRange(size_t begin, size_t end) : begin(begin), end(end) {}
   };
   // Only public for testing.
   std::vector<SortRange> GetSortRanges() const;
 
  private:
+  template <typename Comparator>
+  void SortList(Comparator comparator);
+
   // Tokens corresponding to the [ and ]. The end token is stored in inside an
   // custom parse node so that it can have comments hung off of it.
   Token begin_token_;
   scoped_ptr<EndNode> end_;
   bool prefer_multiline_;
 
   // Owning pointers, use unique_ptr when we can use C++11.
   std::vector<const ParseNode*> contents_;
 
   DISALLOW_COPY_AND_ASSIGN(ListNode);
@@ skipping 107 matching lines @@
   const Token& value() const { return value_; }
   void set_value(const Token& t) { value_ = t; }
 
  private:
   Token value_;
 
   DISALLOW_COPY_AND_ASSIGN(EndNode);
 };
 
 #endif  // TOOLS_GN_PARSE_TREE_H_