Patch PrefHashStoreImpl::PrefHashStoreTransactionImpl::CheckValue

dont-check-pref-hash.patch

# https://github.com/Eloston/ungoogled-chromium/issues/538
--- services/preferences/tracked/pref_hash_store_impl.cc	2018-11-03 23:30:48.000000000 +0800
+++ services/preferences/tracked/pref_hash_store_impl.cc	2018-11-03 23:34:27.000000000 +0800
@@ -156,33 +156,7 @@
 ValueState PrefHashStoreImpl::PrefHashStoreTransactionImpl::CheckValue(
     const std::string& path,
     const base::Value* initial_value) const {
-  std::string last_hash;
-  contents_->GetMac(path, &last_hash);
-
-  if (last_hash.empty()) {
-    // In the absence of a hash for this pref, always trust a NULL value, but
-    // only trust an existing value if the initial hashes dictionary is trusted.
-    if (!initial_value)
-      return ValueState::TRUSTED_NULL_VALUE;
-    else if (super_mac_valid_)
-      return ValueState::TRUSTED_UNKNOWN_VALUE;
-    else
-      return ValueState::UNTRUSTED_UNKNOWN_VALUE;
-  }
-
-  PrefHashCalculator::ValidationResult validation_result =
-      outer_->pref_hash_calculator_.Validate(path, initial_value, last_hash);
-  switch (validation_result) {
-    case PrefHashCalculator::VALID:
-      return ValueState::UNCHANGED;
-    case PrefHashCalculator::VALID_SECURE_LEGACY:
-      return ValueState::SECURE_LEGACY;
-    case PrefHashCalculator::INVALID:
-      return initial_value ? ValueState::CHANGED : ValueState::CLEARED;
-  }
-  NOTREACHED() << "Unexpected PrefHashCalculator::ValidationResult: "
-               << validation_result;
-  return ValueState::UNTRUSTED_UNKNOWN_VALUE;
+  return ValueState::UNCHANGED;
 }
 
 void PrefHashStoreImpl::PrefHashStoreTransactionImpl::StoreHash(