diff --git a/base/numerics/safe_math.h b/base/numerics/safe_math.h
index 3d765c9..9b2177f 100644
--- a/base/numerics/safe_math.h
+++ b/base/numerics/safe_math.h
@@ -80,8 +80,8 @@
 //  CheckedNumeric::Cast<Dst>() - Instance method returning a CheckedNumeric
 //          derived from casting the current instance to a CheckedNumeric of
 //          the supplied destination type.
-//  CheckNum() - Creates a new CheckedNumeric from the underlying type of the
-//          supplied arithmetic, CheckedNumeric, or StrictNumeric type.
+//  MakeCheckedNum() - Creates a new CheckedNumeric from the underlying type of
+//          the supplied arithmetic, CheckedNumeric, or StrictNumeric type.
 //
 // Comparison operations are explicitly not supported because they could result
 // in a crash on an unexpected CHECK condition. You should use patterns like the
@@ -396,7 +396,7 @@
 // Convience wrapper to return a new CheckedNumeric from the provided arithmetic
 // or CheckedNumericType.
 template <typename T>
-constexpr CheckedNumeric<typename UnderlyingType<T>::type> CheckNum(
+constexpr CheckedNumeric<typename UnderlyingType<T>::type> MakeCheckedNum(
     const T value) {
   return value;
 }
@@ -493,7 +493,7 @@
 using internal::IsValidForType;
 using internal::ValueOrDieForType;
 using internal::ValueOrDefaultForType;
-using internal::CheckNum;
+using internal::MakeCheckedNum;
 using internal::CheckMax;
 using internal::CheckMin;
 using internal::CheckAdd;
diff --git a/base/numerics/safe_numerics_unittest.cc b/base/numerics/safe_numerics_unittest.cc
index 7d42a836..56b07427 100644
--- a/base/numerics/safe_numerics_unittest.cc
+++ b/base/numerics/safe_numerics_unittest.cc
@@ -25,7 +25,7 @@
 using base::IsValidForType;
 using base::ValueOrDieForType;
 using base::ValueOrDefaultForType;
-using base::CheckNum;
+using base::MakeCheckedNum;
 using base::CheckMax;
 using base::CheckMin;
 using base::CheckAdd;
@@ -252,7 +252,7 @@
   TEST_EXPECTED_VALUE(0, CheckedNumeric<Dst>(0) & 1);
   TEST_EXPECTED_VALUE(0, CheckedNumeric<Dst>(1) & 0);
   TEST_EXPECTED_VALUE(std::numeric_limits<Dst>::max(),
-                      CheckNum(DstLimits::max()) & -1);
+                      MakeCheckedNum(DstLimits::max()) & -1);
   TEST_EXPECTED_VALUE(1, CheckedNumeric<Dst>(1) | 1);
   TEST_EXPECTED_VALUE(1, CheckedNumeric<Dst>(1) | 0);
   TEST_EXPECTED_VALUE(1, CheckedNumeric<Dst>(0) | 1);
@@ -483,18 +483,22 @@
 
   // Due to differences in float handling between compilers, these aren't
   // compile-time constants everywhere. So, we use run-time tests.
-  EXPECT_EQ(SrcLimits::max(),
-            CheckNum(SrcLimits::max()).Max(DstLimits::lowest()).ValueOrDie());
-  EXPECT_EQ(DstLimits::max(),
-            CheckNum(SrcLimits::lowest()).Max(DstLimits::max()).ValueOrDie());
-  EXPECT_EQ(DstLimits::lowest(),
-            CheckNum(SrcLimits::max()).Min(DstLimits::lowest()).ValueOrDie());
-  EXPECT_EQ(SrcLimits::lowest(),
-            CheckNum(SrcLimits::lowest()).Min(DstLimits::max()).ValueOrDie());
-  EXPECT_EQ(SrcLimits::lowest(), CheckMin(MakeStrictNum(1), CheckNum(0),
+  EXPECT_EQ(
+      SrcLimits::max(),
+      MakeCheckedNum(SrcLimits::max()).Max(DstLimits::lowest()).ValueOrDie());
+  EXPECT_EQ(
+      DstLimits::max(),
+      MakeCheckedNum(SrcLimits::lowest()).Max(DstLimits::max()).ValueOrDie());
+  EXPECT_EQ(
+      DstLimits::lowest(),
+      MakeCheckedNum(SrcLimits::max()).Min(DstLimits::lowest()).ValueOrDie());
+  EXPECT_EQ(
+      SrcLimits::lowest(),
+      MakeCheckedNum(SrcLimits::lowest()).Min(DstLimits::max()).ValueOrDie());
+  EXPECT_EQ(SrcLimits::lowest(), CheckMin(MakeStrictNum(1), MakeCheckedNum(0),
                                           DstLimits::max(), SrcLimits::lowest())
                                      .ValueOrDie());
-  EXPECT_EQ(DstLimits::max(), CheckMax(MakeStrictNum(1), CheckNum(0),
+  EXPECT_EQ(DstLimits::max(), CheckMax(MakeStrictNum(1), MakeCheckedNum(0),
                                        DstLimits::max(), SrcLimits::lowest())
                                   .ValueOrDie());
 }
@@ -868,9 +872,9 @@
   EXPECT_EQ(0, saturated_cast<int>(not_a_number));
 
   // Test the CheckedNumeric value extractions functions.
-  auto int8_min = CheckNum(numeric_limits<int8_t>::min());
-  auto int8_max = CheckNum(numeric_limits<int8_t>::max());
-  auto double_max = CheckNum(numeric_limits<double>::max());
+  auto int8_min = MakeCheckedNum(numeric_limits<int8_t>::min());
+  auto int8_max = MakeCheckedNum(numeric_limits<int8_t>::max());
+  auto double_max = MakeCheckedNum(numeric_limits<double>::max());
   static_assert(
       std::is_same<int16_t,
                    decltype(int8_min.ValueOrDie<int16_t>())::type>::value,
@@ -1015,19 +1019,19 @@
 }
 
 TEST(SafeNumerics, VariadicNumericOperations) {
-  auto a = CheckAdd(1, 2UL, CheckNum(3LL), 4).ValueOrDie();
+  auto a = CheckAdd(1, 2UL, MakeCheckedNum(3LL), 4).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(a)::type>(10), a);
-  auto b = CheckSub(CheckNum(20.0), 2UL, 4).ValueOrDie();
+  auto b = CheckSub(MakeCheckedNum(20.0), 2UL, 4).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(b)::type>(14.0), b);
-  auto c = CheckMul(20.0, CheckNum(1), 5, 3UL).ValueOrDie();
+  auto c = CheckMul(20.0, MakeCheckedNum(1), 5, 3UL).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(c)::type>(300.0), c);
-  auto d = CheckDiv(20.0, 2.0, CheckNum(5LL), -4).ValueOrDie();
+  auto d = CheckDiv(20.0, 2.0, MakeCheckedNum(5LL), -4).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(d)::type>(-.5), d);
-  auto e = CheckMod(CheckNum(20), 3).ValueOrDie();
+  auto e = CheckMod(MakeCheckedNum(20), 3).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(e)::type>(2), e);
-  auto f = CheckLsh(1, CheckNum(2)).ValueOrDie();
+  auto f = CheckLsh(1, MakeCheckedNum(2)).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(f)::type>(4), f);
-  auto g = CheckRsh(4, CheckNum(2)).ValueOrDie();
+  auto g = CheckRsh(4, MakeCheckedNum(2)).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(g)::type>(1), g);
   auto h = CheckRsh(CheckAdd(1, 1, 1, 1), CheckSub(4, 2)).ValueOrDie();
   EXPECT_EQ(static_cast<decltype(h)::type>(1), h);
diff --git a/net/dns/dns_protocol.h b/net/dns/dns_protocol.h
index f808863..416738a2 100644
--- a/net/dns/dns_protocol.h
+++ b/net/dns/dns_protocol.h
@@ -128,7 +128,6 @@
 // DNS reply codes (RCODEs).
 //
 // https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6
-static const uint8_t kRcodeMask = 0xf;
 static const uint8_t kRcodeNOERROR = 0;
 static const uint8_t kRcodeFORMERR = 1;
 static const uint8_t kRcodeSERVFAIL = 2;
diff --git a/net/dns/dns_response.cc b/net/dns/dns_response.cc
index 9896789..f168a255 100644
--- a/net/dns/dns_response.cc
+++ b/net/dns/dns_response.cc
@@ -19,6 +19,12 @@
 
 namespace net {
 
+namespace {
+
+const uint8_t kRcodeMask = 0xf;
+
+}  // namespace
+
 DnsResourceRecord::DnsResourceRecord() {
 }
 
@@ -221,12 +227,12 @@
 
 uint16_t DnsResponse::flags() const {
   DCHECK(parser_.IsValid());
-  return base::NetToHost16(header()->flags) & ~(dns_protocol::kRcodeMask);
+  return base::NetToHost16(header()->flags) & ~(kRcodeMask);
 }
 
 uint8_t DnsResponse::rcode() const {
   DCHECK(parser_.IsValid());
-  return base::NetToHost16(header()->flags) & dns_protocol::kRcodeMask;
+  return base::NetToHost16(header()->flags) & kRcodeMask;
 }
 
 unsigned DnsResponse::answer_count() const {