[ios] Wait for sync query to return before displaying history

ios/chrome/browser/ui/history/history_collection_view_controller.mm

Index: ios/chrome/browser/ui/history/history_collection_view_controller.mm
diff --git a/ios/chrome/browser/ui/history/history_collection_view_controller.mm b/ios/chrome/browser/ui/history/history_collection_view_controller.mm
index c2c010360832627a6b280f0861faedca1db39484..fe83357656c502899d7d590d44fc44a0685eccf8 100644
--- a/ios/chrome/browser/ui/history/history_collection_view_controller.mm
+++ b/ios/chrome/browser/ui/history/history_collection_view_controller.mm
@@ -107,6 +107,9 @@ const CGFloat kSeparatorInset = 10;
 - (void)removeSelectedItemsFromCollection;
 // Removes all items in the collection that are not included in entries.
 - (void)filterForHistoryEntries:(NSArray*)entries;
+// Adds loading indicator to the top of the history collection, if one is not
+// already present.
+- (void)addLoadingIndicator;
 // Displays context menu on cell pressed with gestureRecognizer.
 - (void)displayContextMenuInvokedByGestureRecognizer:
     (UILongPressGestureRecognizer*)gestureRecognizer;
@@ -315,15 +318,15 @@ const CGFloat kSeparatorInset = 10;
 - (void)historyServiceFacade:(HistoryServiceFacade*)facade
        didReceiveQueryResult:(HistoryServiceFacade::QueryResult)result {
   self.loading = NO;
-  // Remove loading indicator.
-  CollectionViewItem* headerItem = [self.collectionViewModel
-      itemAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]];
-  if ([headerItem.cellClass isSubclassOfClass:[ActivityIndicatorCell class]]) {
-    [self.collectionViewModel removeItemWithType:kItemTypeEnumZero
-                       fromSectionWithIdentifier:kSectionIdentifierEnumZero];
-    [self.collectionView
-        deleteItemsAtIndexPaths:@[ [NSIndexPath indexPathForItem:0
-                                                       inSection:0] ]];
+  // If history sync is enabled and there hasn't been a response from synced
+  // history, try fetching again.
+  SyncSetupService* syncSetupService =
+      SyncSetupServiceFactory::GetForBrowserState(_browserState);
+  if (syncSetupService->IsSyncEnabled() &&
+      syncSetupService->IsDataTypeEnabled(syncer::HISTORY_DELETE_DIRECTIVES) &&
+      !result.web_history_returned) {

[sczs, 2016/12/20 22:49:48]

Should this be !result.sync_returned ?!

[Jackie Quinn, 2016/12/20 23:12:04]

Ah yes thanks. Last minute variable name change 🙃

+    [self showHistoryMatchingQuery:_currentQuery];
+    return;
   }
 
   // If there are no results and no URLs have been loaded, report that no
@@ -526,24 +529,9 @@ const CGFloat kSeparatorInset = 10;
 - (void)fetchHistoryForQuery:(NSString*)query
                  priorToTime:(const base::Time&)time {
   self.loading = YES;
-  // Add loading indicator if nothing else is shown.
+  // Add loading indicator if no items are shown.
   if (!self.hasHistoryEntries && !self.isSearching) {
-    [self.collectionView performBatchUpdates:^{
-      NSIndexPath* indexPath = [NSIndexPath indexPathForItem:0 inSection:0];
-      if ([self.collectionViewModel hasItemAtIndexPath:indexPath]) {
-        [self.collectionViewModel
-                   removeItemWithType:kItemTypeEnumZero
-            fromSectionWithIdentifier:kSectionIdentifierEnumZero];
-        [self.collectionView deleteItemsAtIndexPaths:@[ indexPath ]];
-      }
-      CollectionViewItem* loadingIndicatorItem = [[[CollectionViewItem alloc]
-          initWithType:kItemTypeEnumZero] autorelease];
-      loadingIndicatorItem.cellClass = [ActivityIndicatorCell class];
-      [self.collectionViewModel addItem:loadingIndicatorItem
-                toSectionWithIdentifier:kEntriesStatusSectionIdentifier];
-      [self.collectionView insertItemsAtIndexPaths:@[ indexPath ]];
-    }
-                                  completion:nil];
+    [self addLoadingIndicator];
   }
 
   BOOL fetchAllHistory = !query || [query isEqualToString:@""];
@@ -557,7 +545,6 @@ const CGFloat kSeparatorInset = 10;
   options.max_count = kMaxFetchCount;
   options.matching_algorithm =
       query_parser::MatchingAlgorithm::ALWAYS_PREFIX_SEARCH;
-  _historyServiceFacade->QueryOtherFormsOfBrowsingHistory();
   _historyServiceFacade->QueryHistory(queryString, options);
   // Also determine whether notice regarding other forms of browsing history
   // should be shown.
@@ -667,6 +654,31 @@ const CGFloat kSeparatorInset = 10;
   [self removeSelectedItemsFromCollection];
 }
 
+- (void)addLoadingIndicator {
+  NSIndexPath* indexPath = [NSIndexPath indexPathForItem:0 inSection:0];

[sczs, 2016/12/20 22:49:48]

Could self.loading be used here instead of checking the cell subclass?

[Jackie Quinn, 2016/12/20 23:12:04]

Not necessarily. Presence/absence of the loading indicator right now is not tied
to self.loading, so I think it's better to check for the actual item.

+  if ([self.collectionViewModel hasItemAtIndexPath:indexPath] &&
+      [[[self.collectionViewModel itemAtIndexPath:indexPath] cellClass]
+          isSubclassOfClass:[ActivityIndicatorCell class]]) {
+    // Do not add indicator a sectond time.
+    return;
+  }
+
+  [self.collectionView performBatchUpdates:^{
+    if ([self.collectionViewModel hasItemAtIndexPath:indexPath]) {
+      [self.collectionViewModel removeItemWithType:kItemTypeEnumZero
+                         fromSectionWithIdentifier:kSectionIdentifierEnumZero];
+      [self.collectionView deleteItemsAtIndexPaths:@[ indexPath ]];
+    }
+    CollectionViewItem* loadingIndicatorItem = [[[CollectionViewItem alloc]
+        initWithType:kItemTypeEnumZero] autorelease];
+    loadingIndicatorItem.cellClass = [ActivityIndicatorCell class];
+    [self.collectionViewModel addItem:loadingIndicatorItem
+              toSectionWithIdentifier:kEntriesStatusSectionIdentifier];
+    [self.collectionView insertItemsAtIndexPaths:@[ indexPath ]];
+  }
+                                completion:nil];
+}
+
 #pragma mark Context Menu
 
 - (void)displayContextMenuInvokedByGestureRecognizer: