base::Hash: Minor improvements to documentation and testing.

base/hash.h

 // Copyright (c) 2011 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_HASH_H_
 #define BASE_HASH_H_
 
 #include <limits>
 #include <string>
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/logging.h"
 
 namespace base {
 
 // WARNING: This hash function should not be used for any cryptographic purpose.
 BASE_EXPORT uint32 SuperFastHash(const char* data, int len);
 
-// Computes the hash of a string |key| of a given |length|. |key| does not need
-// to be null-terminated, and may contain null bytes.
+// Computes a hash of a memory buffer |data| of a given |length|.
 // WARNING: This hash function should not be used for any cryptographic purpose.
-inline uint32 Hash(const char* key, size_t length) {
+inline uint32 Hash(const char* data, size_t length) {
   if (length > static_cast<size_t>(std::numeric_limits<int>::max())) {
     NOTREACHED();
     return 0;
   }
-  return SuperFastHash(key, static_cast<int>(length));
+  return SuperFastHash(data, static_cast<int>(length));
 }
 
-// Computes the hash of a string |key|.
+// Computes a hash of a string |str|.
 // WARNING: This hash function should not be used for any cryptographic purpose.
-inline uint32 Hash(const std::string& key) {
-  return Hash(key.data(), key.size());
+inline uint32 Hash(const std::string& str) {
+  return Hash(str.data(), str.size());
 }
 
 }  // namespace base
 
 #endif  // BASE_HASH_H_