Improve grammar in some comments.

base/containers/small_map.h

 // Copyright (c) 2012 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 BASE_CONTAINERS_SMALL_MAP_H_
 #define BASE_CONTAINERS_SMALL_MAP_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 14 matching lines @@
 // --------------------------------
 //
 //  - std::map should be the default if you're not sure, since it's the most
 //    difficult to mess up. Generally this is backed by a red-black tree. It
 //    will generate a lot of code (if you use a common key type like int or
 //    string the linker will probably emiminate the duplicates). It will
 //    do heap allocations for each element.
 //
 //  - If you only ever keep a couple of items and have very simple usage,
 //    consider whether a using a vector and brute-force searching it will be
-//    the most efficient. It's not a lot of generated code (less then a
+//    the most efficient. It's not a lot of generated code (less than a
 //    red-black tree if your key is "weird" and not eliminated as duplicate of
 //    something else) and will probably be faster and do fewer heap allocations
 //    than std::map if you have just a couple of items.
 //
 //  - base::hash_map should be used if you need O(1) lookups. It may waste
 //    space in the hash table, and it can be easy to write correct-looking
 //    code with the default hash function being wrong or poorly-behaving.
 //
 //  - SmallMap combines the performance benefits of the brute-force-searched
 //    vector for small cases (no extra heap allocations), but can efficiently
@@ skipping 598 matching lines @@
           typename Functor>
 inline bool SmallMap<NormalMap, kArraySize, EqualKey,
                      Functor>::iterator::operator!=(
     const const_iterator& other) const {
   return other != *this;
 }
 
 }  // namespace base
 
 #endif  // BASE_CONTAINERS_SMALL_MAP_H_