3 files changed, 6 insertions, 31 deletions
diff --git a/base/strings/string16.h b/base/strings/string16.h
index af44a5c..e47669c 100644
--- a/base/strings/string16.h
+++ b/base/strings/string16.h
@@ -29,8 +29,6 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
-
-#include <functional>
 #include <string>
 
 #include "base/base_export.h"
@@ -184,21 +182,6 @@ BASE_EXPORT extern void PrintTo(const string16& str, std::ostream* out);
 extern template
 class BASE_EXPORT std::basic_string<base::char16, base::string16_char_traits>;
 
-// Specialize std::hash for base::string16. Although the style guide forbids
-// this in general, it is necessary for consistency with WCHAR_T_IS_UTF16
-// platforms, where base::string16 is a type alias for std::wstring.
-namespace std {
-template<>
-struct hash<base::string16> {
-  std::size_t operator()(const base::string16& s) const {
-    std::size_t result = 0;
-    for (base::char16 c : s)
-      result = (result * 131) + c;
-    return result;
-  }
-};
-}  // namespace std
-
 #endif  // WCHAR_T_IS_UTF32
 
 #endif  // BASE_STRINGS_STRING16_H_
diff --git a/base/strings/string16_unittest.cc b/base/strings/string16_unittest.cc
index 0d2ca80..4e58218 100644
--- a/base/strings/string16_unittest.cc
+++ b/base/strings/string16_unittest.cc
@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 #include <sstream>
-#include <unordered_set>
 
 #include "base/strings/string16.h"
 
@@ -12,6 +11,8 @@
 
 namespace base {
 
+#if defined(WCHAR_T_IS_UTF32)
+
 // We define a custom operator<< for string16 so we can use it with logging.
 // This tests that conversion.
 TEST(String16Test, OutputStream) {
@@ -52,15 +53,6 @@ TEST(String16Test, OutputStream) {
   }
 }
 
-TEST(String16Test, Hash) {
-  string16 str1 = ASCIIToUTF16("hello");
-  string16 str2 = ASCIIToUTF16("world");
-
-  std::unordered_set<string16> set;
-
-  set.insert(str1);
-  EXPECT_EQ(1u, set.count(str1));
-  EXPECT_EQ(0u, set.count(str2));
-}
+#endif
 
 }  // namespace base
diff --git a/base/strings/string_piece.h b/base/strings/string_piece.h
index 92634b9..31e7596 100644
--- a/base/strings/string_piece.h
+++ b/base/strings/string_piece.h
@@ -439,9 +439,9 @@ BASE_EXPORT std::ostream& operator<<(std::ostream& o,
 // We provide appropriate hash functions so StringPiece and StringPiece16 can
 // be used as keys in hash sets and maps.
 
-// This hash function is copied from base/strings/string16.h. We don't use the
-// ones already defined for string and string16 directly because it would
-// require the string constructors to be called, which we don't want.
+// This hash function is copied from base/containers/hash_tables.h. We don't
+// use the ones already defined for string and string16 directly because it
+// would require the string constructors to be called, which we don't want.
 #define HASH_STRING_PIECE(StringPieceType, string_piece)                \
   std::size_t result = 0;                                               \
   for (StringPieceType::const_iterator i = string_piece.begin();        \