[ModelTypeWorker] Store SyncEntities if encryption pending

This CL changes the way we process incoming SyncEntities when decryption
is pending. After the change:
 - PopulateUpdateResponseData() early returns and does not populate
   anything if decryption is pending.
 - ProcessGetUpdatesResponse() then stores the original SyncEntity
   instead of the previous (partially) populated UpdateResponseData.
 - DecryptStoredEntities() gets much simpler because it can now reuse
   PopulateUpdateResponseData() and does not have to duplicate the
   decryption logic.

As a result this CL reconciles all bookmarks adaptations into a single
place in PopulateUpdateResponseData().

This CL does not introduce any behavioral change.

Bug: 1007199
Change-Id: I5ebbfcbaf5dd6bd677aba1697e7ee8d8cd08d75f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1827427
Commit-Queue: Jan Krcal <jkrcal@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#723431}

components/sync/engine_impl/bookmark_update_preprocessing.cc

@@ -142,25 +142,4 @@ void AdaptGuidForBookmark(const sync_pb::SyncEntity& update_entity,
   }
 }
 
-void AdaptGuidForBookmarkEntityData(EntityData* entity_data) {
-  DCHECK(entity_data);
-  DCHECK(entity_data->specifics.has_bookmark());
-  DCHECK(!entity_data->specifics.has_encrypted());
-
-  if (entity_data->is_deleted() ||
-      !entity_data->server_defined_unique_tag.empty()) {
-    return;
-  }
-
-  if (entity_data->specifics.bookmark().has_guid()) {
-    LogGuidSource(BookmarkGuidSource::kSpecifics);
-  } else if (base::IsValidGUID(entity_data->originator_client_item_id)) {
-    entity_data->specifics.mutable_bookmark()->set_guid(
-        entity_data->originator_client_item_id);
-    LogGuidSource(BookmarkGuidSource::kValidOCII);
-  } else {
-    LogGuidSource(BookmarkGuidSource::kLeftEmpty);
-  }
-}
-
 }  // namespace syncer

components/sync/engine_impl/bookmark_update_preprocessing.h

@@ -37,11 +37,6 @@ void AdaptTitleForBookmark(const sync_pb::SyncEntity& update_entity,
 void AdaptGuidForBookmark(const sync_pb::SyncEntity& update_entity,
                           sync_pb::EntitySpecifics* specifics);
 
-// Analogous to AdaptGuidForBookmark() but deals with EntityData structs.
-// |entity_data| must not be null.
-// TODO(crbug.com/1007199): Reconcile with AdaptGuidForBookmark().
-void AdaptGuidForBookmarkEntityData(EntityData* entity_data);
-
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_IMPL_BOOKMARK_UPDATE_PREPROCESSING_H_

components/sync/engine_impl/model_type_worker.h

@@ -231,10 +231,10 @@ class ModelTypeWorker : public UpdateHandler,
   // Interface used to access and send nudges to the sync scheduler. Not owned.
   NudgeHandler* nudge_handler_;
 
-  // A map of update responses, keyed by server_id.
-  // Holds updates encrypted with pending keys.
-  std::map<std::string, std::unique_ptr<UpdateResponseData>>
-      entries_pending_decryption_;
+  // A map of sync entities, keyed by server_id. Holds updates encrypted with
+  // pending keys. Entries are stored in a map for de-duplication (applying only
+  // the latest).
+  std::map<std::string, sync_pb::SyncEntity> entries_pending_decryption_;
 
   // Accumulates all the updates from a single GetUpdates cycle in memory so
   // they can all be sent to the processor at once.

components/sync/protocol/proto_memory_estimations.cc

@@ -127,6 +127,7 @@ INSTANTIATE(EntityMetadata)
 INSTANTIATE(EntitySpecifics)
 INSTANTIATE(ModelTypeState)
 INSTANTIATE(PersistedEntityData)
+INSTANTIATE(SyncEntity)
 INSTANTIATE(UniquePosition)
 
 }  // namespace sync_pb