Remove TransportSecurityState::AddOrUpdateEnabledPKPHosts.

Unused since https://crrev.com/230996f183bc6eb2f8ec2a39f7d19f9d6267ec84

Bug: 779166
Change-Id: I57e2f6253b834734829fd7acacc6254afbe07081
Reviewed-on: https://chromium-review.googlesource.com/c/1298418Reviewed-by: David Benjamin <davidben@chromium.org>
Commit-Queue: Matt Mueller <mattm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602518}

net/http/transport_security_state.cc

@@ -1301,14 +1301,6 @@ void TransportSecurityState::AddOrUpdateEnabledSTSHosts(
   enabled_sts_hosts_[hashed_host] = state;
 }
 
-void TransportSecurityState::AddOrUpdateEnabledPKPHosts(
-    const std::string& hashed_host,
-    const PKPState& state) {
-  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
-  DCHECK(state.HasPublicKeyPins());
-  enabled_pkp_hosts_[hashed_host] = state;
-}
-
 void TransportSecurityState::AddOrUpdateEnabledExpectCTHosts(
     const std::string& hashed_host,
     const ExpectCTState& state) {

net/http/transport_security_state.h

@@ -406,13 +406,6 @@ class NET_EXPORT TransportSecurityState {
   void AddOrUpdateEnabledSTSHosts(const std::string& hashed_host,
                                   const STSState& state);
 
-  // Inserts |state| into |enabled_pkp_hosts_| under the key |hashed_host|.
-  // |hashed_host| is already in the internal representation.
-  // Note: This is only used for serializing/deserializing the
-  // TransportSecurityState.
-  void AddOrUpdateEnabledPKPHosts(const std::string& hashed_host,
-                                  const PKPState& state);
-
   // Inserts |state| into |enabled_expect_ct_hosts_| under the key
   // |hashed_host|. |hashed_host| is already in the internal representation.
   // Note: This is only used for serializing/deserializing the