Remove policy atomic groups logic

Bug: 989734
Change-Id: I0c9a6c29bf504838595cddf3109870130fa12881
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1731171Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Yann Dago <ydago@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683305}

components/policy/core/common/policy_service_impl.cc

@@ -230,11 +230,9 @@ void PolicyServiceImpl::MergeAndTriggerUpdates() {
   PolicyListMerger policy_list_merger(std::move(policy_lists_to_merge));
   PolicyDictionaryMerger policy_dictionary_merger(
       std::move(policy_dictionaries_to_merge));
-  PolicyGroupMerger policy_group_merger;
 
   for (auto it = bundle.begin(); it != bundle.end(); ++it) {
-    it->second->MergeValues(
-        {&policy_list_merger, &policy_dictionary_merger, &policy_group_merger});
+    it->second->MergeValues({&policy_list_merger, &policy_dictionary_merger});
   }
 
   // Swap first, so that observers that call GetPolicies() see the current

components/policy/core/common/policy_service_impl_unittest.cc

@@ -904,7 +904,6 @@ TEST_F(PolicyServiceTest, GroupPoliciesMerging) {
   merged.AddWarning(IDS_POLICY_CONFLICT_DIFF_VALUE);
   expected_chrome.Set(key::kExtensionInstallForcelist, merged.DeepCopy());
   expected_chrome.Set(key::kExtensionInstallBlacklist, std::move(merged));
-  entry_list_3.SetIgnoredByPolicyAtomicGroup();
   expected_chrome.Set(key::kExtensionInstallWhitelist, std::move(entry_list_3));
 
   provider0_.UpdatePolicy(std::move(policy_bundle1));