Introduce ReferenceDelegates (#1222)

* Bump sequence number on resume token refresh

* Style

* Fix comment formatting

* Add FSTReferenceDelegate definition and documentation

* Add methods to return nil for delegates, wire up inMemoryPins

* Add hook for removing a reference

* Start work on reference delegates

* Fix up tests to support adding documents at a sequence number

* Implement removing references

* Remove from target when dropped from local view

* Fix warning

* Add hooks for removal from mutation queue

* Add hooks for limbo document updates

* Style

* Drop commented-out code

* Fixup after merging master

* Drop sequence number plumbing

* Style

* Drop errant semicolon

1 files changed, 6 insertions, 5 deletions

diff --git a/Firestore/Source/Local/FSTMemoryMutationQueue.mm b/Firestore/Source/Local/FSTMemoryMutationQueue.mm
index b0c8760..e05ee64 100644
--- a/Firestore/Source/Local/FSTMemoryMutationQueue.mm
+++ b/Firestore/Source/Local/FSTMemoryMutationQueue.mm
@@ -18,6 +18,7 @@
 
 #import "Firestore/Source/Core/FSTQuery.h"
 #import "Firestore/Source/Local/FSTDocumentReference.h"
+#import "Firestore/Source/Local/FSTMemoryPersistence.h"
 #import "Firestore/Source/Model/FSTMutation.h"
 #import "Firestore/Source/Model/FSTMutationBatch.h"
 #import "Firestore/Source/Util/FSTAssert.h"
@@ -73,14 +74,13 @@ static const NSComparator NumberComparator = ^NSComparisonResult(NSNumber *left,
 
 @end
 
-@implementation FSTMemoryMutationQueue
-
-+ (instancetype)mutationQueue {
-  return [[FSTMemoryMutationQueue alloc] init];
+@implementation FSTMemoryMutationQueue {
+  FSTMemoryPersistence *_persistence;
 }
 
-- (instancetype)init {
+- (instancetype)initWithPersistence:(FSTMemoryPersistence *)persistence {
   if (self = [super init]) {
+    _persistence = persistence;
     _queue = [NSMutableArray array];
     _batchesByDocumentKey =
         [FSTImmutableSortedSet setWithComparator:FSTDocumentReferenceComparatorByKey];
@@ -348,6 +348,7 @@ static const NSComparator NumberComparator = ^NSComparisonResult(NSNumber *left,
     for (FSTMutation *mutation in batch.mutations) {
       const DocumentKey &key = mutation.key;
       [garbageCollector addPotentialGarbageKey:key];
+      [_persistence.referenceDelegate removeMutationReference:key];
 
       FSTDocumentReference *reference = [[FSTDocumentReference alloc] initWithKey:key ID:batchID];
       references = [references setByRemovingObject:reference];