Add missing Porting Notes (#1327)

Author: schmidt-sebastian

packages/firestore/src/core/sync_engine.ts

@@ -1073,11 +1073,15 @@ export class SyncEngine implements RemoteSyncer, SharedClientStateSyncer {
     }
   }
 
+  // PORTING NOTE: Multi-tab only. In other clients, LocalStore is unaware of
+  // the online state.
   enableNetwork(): Promise<void> {
     this.localStore.setNetworkEnabled(true);
     return this.remoteStore.enableNetwork();
   }
 
+  // PORTING NOTE: Multi-tab only. In other clients, LocalStore is unaware of
+  // the online state.
   disableNetwork(): Promise<void> {
     this.localStore.setNetworkEnabled(false);
     return this.remoteStore.disableNetwork();

packages/firestore/src/core/target_id_generator.ts

@@ -65,6 +65,7 @@ export class TargetIdGenerator {
    * Returns the ID that follows the given ID. Subsequent calls to `next()`
    * use the newly returned target ID as their base.
    */
+  // PORTING NOTE: Multi-tab only.
   after(targetId: TargetId): TargetId {
     this.seek(targetId + (1 << RESERVED_BITS));
     return this.next();

packages/firestore/src/local/local_store.ts

@@ -179,6 +179,8 @@ export class LocalStore {
    * In response the local store switches the mutation queue to the new user and
    * returns any resulting document changes.
    */
+  // PORTING NOTE: Android and iOS only return the documents affected by the
+  // change.
   handleUserChange(user: User): Promise<UserChangeResult> {
     return this.persistence.runTransaction(
       'Handle user change',

packages/firestore/src/local/mutation_queue.ts

@@ -73,6 +73,7 @@ export interface MutationQueue {
    * `removeMutationBatches()` has been called. Secondary clients return a
    * cached result until `removeCachedMutationKeys()` is invoked.
    */
+  // PORTING NOTE: Multi-tab only.
   lookupMutationKeys(
     transaction: PersistenceTransaction,
     batchId: BatchId

packages/firestore/src/local/query_cache.ts

@@ -192,6 +192,7 @@ export interface QueryCache {
    * Allocated target IDs are persisted and `allocateTargetId()` will never
    * return the same ID twice.
    */
+  // PORTING NOTE: Multi-tab only.
   allocateTargetId(
     transaction: PersistenceTransaction
   ): PersistencePromise<TargetId>;