Check alpha-sorting of includes during presubmit.

src/zone.h

 // Copyright 2012 the V8 project 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 V8_ZONE_H_
 #define V8_ZONE_H_
 
 #include "src/allocation.h"
 #include "src/checks.h"
+#include "src/globals.h"
 #include "src/hashmap.h"
-#include "src/globals.h"
 #include "src/list.h"
 #include "src/splay-tree.h"
 
 namespace v8 {
 namespace internal {
 
 
 class Segment;
 class Isolate;
 
@@ skipping 212 matching lines @@
   void operator delete(void* pointer) { UNREACHABLE(); }
   void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); }
 };
 
 
 typedef TemplateHashMapImpl<ZoneAllocationPolicy> ZoneHashMap;
 
 } }  // namespace v8::internal
 
 #endif  // V8_ZONE_H_