Don't use identity as hash function for integers.

src/base/functional.h

Index: src/base/functional.h
diff --git a/src/base/functional.h b/src/base/functional.h
index 60f93ddad5dfbac1059c32d1f58cbac0402258ef..d815c7214226cfd2e45c002144dac486d39ab59f 100644
--- a/src/base/functional.h
+++ b/src/base/functional.h
@@ -76,11 +76,11 @@ inline size_t hash_combine(T const& v, Ts const&... vs) {
 V8_BASE_HASH_VALUE_TRIVIAL(bool)
 V8_BASE_HASH_VALUE_TRIVIAL(unsigned char)
 V8_BASE_HASH_VALUE_TRIVIAL(unsigned short)  // NOLINT(runtime/int)
-V8_BASE_HASH_VALUE_TRIVIAL(unsigned int)
 #undef V8_BASE_HASH_VALUE_TRIVIAL
 
-size_t hash_value(unsigned long v);       // NOLINT(runtime/int)
-size_t hash_value(unsigned long long v);  // NOLINT(runtime/int)
+size_t hash_value(unsigned int);
+size_t hash_value(unsigned long);       // NOLINT(runtime/int)
+size_t hash_value(unsigned long long);  // NOLINT(runtime/int)
 
 #define V8_BASE_HASH_VALUE_SIGNED(type)            \
   inline size_t hash_value(signed type v) {        \