Add parsing for RFC 5280's InhibitAnyPolicy.

net/cert/internal/parse_certificate.cc

Index: net/cert/internal/parse_certificate.cc
diff --git a/net/cert/internal/parse_certificate.cc b/net/cert/internal/parse_certificate.cc
index 6cfc4b5afeb51a12ea96db689d9c4af7f6b121b5..78baaac89424c9fef2238e2052bd3a6811f199b5 100644
--- a/net/cert/internal/parse_certificate.cc
+++ b/net/cert/internal/parse_certificate.cc
@@ -551,6 +551,16 @@ der::Input AdOcspOid() {
   return der::Input(oid);
 }
 
+der::Input InhibitAnyPolicyOid() {
+  // From RFC 5280:
+  //
+  //     id-ce-inhibitAnyPolicy OBJECT IDENTIFIER ::=  { id-ce 54 }
+  //
+  // In dotted notation: 2.5.29.54
+  static const uint8_t oid[] = {0x55, 0x1d, 0x36};
+  return der::Input(oid);
+}
+
 NET_EXPORT bool ParseExtensions(
     const der::Input& extensions_tlv,
     std::map<der::Input, ParsedExtension>* extensions) {
@@ -794,4 +804,24 @@ bool ParsePolicyConstraints(const der::Input& policy_constraints_tlv,
   return true;
 }
 
+// From RFC 5280:
+//
+//   InhibitAnyPolicy ::= SkipCerts
+//
+//   SkipCerts ::= INTEGER (0..MAX)
+bool ParseInhibitAnyPolicy(const der::Input& inhibit_any_policy_tlv,
+                           uint8_t* out) {
+  der::Parser parser(inhibit_any_policy_tlv);
+
+  // TODO(eroman): Surface reason for failure if length was longer than uint8.
+  if (!parser.ReadUint8(out))
+    return false;
+
+  // There should be no remaining data.
+  if (parser.HasMore())
+    return false;
+
+  return true;
+}
+
 }  // namespace net