[sync] Relax failing DCHECK due to SyncData logging

SyncData::ToString() is used for logging and, starting with
https://crrev.com/c/2562659, it can DCHECK-fail if the sync entity's
title is empty.

This patch removes the DCHECK from SyncData::GetTitle(), since it
seems overly strict, and the main calling site in
SyncableServiceBasedBridge already verifies that the title is non-empty.
To make this more obvious, an additional DCHECKs is introduced (which
is redundant with pre-existing DCHECKs) and two functions renamed for
clarity.

Change-Id: Ib499e6a07132ab21033d83a241e5e380226913b0
Fixed: 1156130
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2577468
Auto-Submit: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Maksim Moskvitin <mmoskvitin@google.com>
Reviewed-by: Maksim Moskvitin <mmoskvitin@google.com>
Cr-Commit-Position: refs/heads/master@{#834673}

components/sync/model/sync_data.cc

@@ -102,8 +102,6 @@ ClientTagHash SyncData::GetClientTagHash() const {
 }
 
 const std::string& SyncData::GetTitle() const {
-  // TODO(zea): set this for data coming from the syncer too.
-  DCHECK(immutable_entity_.Get().has_non_unique_name());
   return immutable_entity_.Get().non_unique_name();
 }
 

components/sync/model/sync_data_unittest.cc

@@ -54,6 +54,7 @@ TEST_F(SyncDataTest, CreateLocalData) {
   EXPECT_EQ(kDatatype, data.GetDataType());
   EXPECT_EQ(kNonUniqueTitle, data.GetTitle());
   EXPECT_TRUE(data.GetSpecifics().has_preference());
+  EXPECT_FALSE(data.ToString().empty());
 }
 
 TEST_F(SyncDataTest, CreateRemoteData) {
@@ -65,6 +66,7 @@ TEST_F(SyncDataTest, CreateRemoteData) {
   EXPECT_EQ(ClientTagHash::FromUnhashed(PREFERENCES, kSyncTag),
             data.GetClientTagHash());
   EXPECT_TRUE(data.GetSpecifics().has_preference());
+  EXPECT_FALSE(data.ToString().empty());
 }
 
 }  // namespace

components/sync/model_impl/syncable_service_based_bridge.cc

@@ -42,7 +42,7 @@ std::unique_ptr<EntityData> ConvertPersistedToEntityData(
   return entity_data;
 }
 
-sync_pb::PersistedEntityData CreatePersistedFromEntityData(
+sync_pb::PersistedEntityData CreatePersistedFromRemoteData(
     const EntityData& entity_data) {
   sync_pb::PersistedEntityData persisted;
   persisted.set_name(entity_data.name);
@@ -50,10 +50,12 @@ sync_pb::PersistedEntityData CreatePersistedFromEntityData(
   return persisted;
 }
 
-sync_pb::PersistedEntityData CreatePersistedFromSyncData(
+sync_pb::PersistedEntityData CreatePersistedFromLocalData(
     const SyncData& sync_data) {
   DCHECK(sync_data.IsLocal());
+  DCHECK(sync_data.IsValid());
   DCHECK(!sync_data.GetTitle().empty());
+
   sync_pb::PersistedEntityData persisted;
   persisted.set_name(sync_data.GetTitle());
   *persisted.mutable_specifics() = sync_data.GetSpecifics();
@@ -149,7 +151,7 @@ class LocalChangeProcessor : public SyncChangeProcessor {
 
           (*in_memory_store_)[storage_key] = change.sync_data().GetSpecifics();
           sync_pb::PersistedEntityData persisted_entity =
-              CreatePersistedFromSyncData(change.sync_data());
+              CreatePersistedFromLocalData(change.sync_data());
           batch->WriteData(storage_key, persisted_entity.SerializeAsString());
 
           other_->Put(storage_key,
@@ -564,7 +566,7 @@ SyncChangeList SyncableServiceBasedBridge::StoreAndConvertRemoteChanges(
 
         batch->WriteData(
             storage_key,
-            CreatePersistedFromEntityData(change->data()).SerializeAsString());
+            CreatePersistedFromRemoteData(change->data()).SerializeAsString());
         in_memory_store_[storage_key] = change->data().specifics;
         break;
       }