[ios] Inserts and deletes history items in the same BatchUpdates block

BUG=707241

Review-Url: https://codereview.chromium.org/2800473004
Cr-Commit-Position: refs/heads/master@{#462784}

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

@@ -108,14 +108,20 @@ const CGFloat kSeparatorInset = 10;
 // the empty string, all history is fetched.
 - (void)fetchHistoryForQuery:(NSString*)query
                  priorToTime:(const base::Time&)time;
+// Updates various elements after history items have been deleted from the
+// CollectionView.
+- (void)updateCollectionViewAfterDeletingEntries;
 // Updates header section to provide relevant information about the currently
 // displayed history entries.
 - (void)updateEntriesStatusMessage;
 // Removes selected items from the visible collection, but does not delete them
 // from browser history.
 - (void)removeSelectedItemsFromCollection;
-// Removes all items in the collection that are not included in entries.
+// Selects all items in the collection that are not included in entries.
 - (void)filterForHistoryEntries:(NSArray*)entries;
+// Deletes all items in the collection which indexes are included in indexArray,
+// needs to be run inside a performBatchUpdates block.
+- (void)deleteItemsFromCollectionViewModelWithIndex:(NSArray*)indexArray;
 // Adds loading indicator to the top of the history collection, if one is not
 // already present.
 - (void)addLoadingIndicator;
@@ -370,16 +376,20 @@ const CGFloat kSeparatorInset = 10;
       }
     }
     [self.delegate historyCollectionViewControllerDidChangeEntries:self];
+    if (([self isSearching] && [searchQuery length] > 0 &&
+         [self.currentQuery isEqualToString:searchQuery]) ||
+        self.filterQueryResult) {
+      // If in search mode, filter out entries that are not
+      // part of the search result.
+      [self filterForHistoryEntries:filterResults];
+      NSArray* deletedIndexPaths =
+          self.collectionView.indexPathsForSelectedItems;
+      [self deleteItemsFromCollectionViewModelWithIndex:deletedIndexPaths];
+      self.filterQueryResult = NO;
+    }
   }
       completion:^(BOOL) {
-        if (([self isSearching] && [searchQuery length] > 0 &&
-             [self.currentQuery isEqualToString:searchQuery]) ||
-            self.filterQueryResult) {
-          // If in search mode, filter out entries that are not
-          // part of the search result.
-          [self filterForHistoryEntries:filterResults];
-          self.filterQueryResult = NO;
-        }
+        [self updateCollectionViewAfterDeletingEntries];
       }];
 }
 
@@ -564,6 +574,15 @@ const CGFloat kSeparatorInset = 10;
   _historyServiceFacade->QueryOtherFormsOfBrowsingHistory();
 }
 
+- (void)updateCollectionViewAfterDeletingEntries {
+  // If only the header section remains, there are no history entries.
+  if ([self.collectionViewModel numberOfSections] == 1) {
+    self.entriesType = NO_ENTRIES;
+  }
+  [self updateEntriesStatusMessage];
+  [self.delegate historyCollectionViewControllerDidChangeEntries:self];
+}
+
 - (void)updateEntriesStatusMessage {
   CollectionViewItem* entriesStatusItem = nil;
   if (!self.hasHistoryEntries) {
@@ -618,28 +637,27 @@ const CGFloat kSeparatorInset = 10;
 - (void)removeSelectedItemsFromCollection {
   NSArray* deletedIndexPaths = self.collectionView.indexPathsForSelectedItems;
   [self.collectionView performBatchUpdates:^{
-    [self collectionView:self.collectionView
-        willDeleteItemsAtIndexPaths:deletedIndexPaths];
-    [self.collectionView deleteItemsAtIndexPaths:deletedIndexPaths];
-
-    // Remove any empty sections, except the header section.
-    for (int section = self.collectionView.numberOfSections - 1; section > 0;
-         --section) {
-      if (![self.collectionViewModel numberOfItemsInSection:section]) {
-        [self.entryInserter removeSection:section];
-      }
-    }
+    [self deleteItemsFromCollectionViewModelWithIndex:deletedIndexPaths];
   }
       completion:^(BOOL) {
-        // If only the header section remains, there are no history entries.
-        if ([self.collectionViewModel numberOfSections] == 1) {
-          self.entriesType = NO_ENTRIES;
-        }
-        [self updateEntriesStatusMessage];
-        [self.delegate historyCollectionViewControllerDidChangeEntries:self];
+        [self updateCollectionViewAfterDeletingEntries];
       }];
 }
 
+- (void)deleteItemsFromCollectionViewModelWithIndex:(NSArray*)indexArray {
+  [self collectionView:self.collectionView
+      willDeleteItemsAtIndexPaths:indexArray];
+  [self.collectionView deleteItemsAtIndexPaths:indexArray];
+
+  // Remove any empty sections, except the header section.
+  for (int section = self.collectionView.numberOfSections - 1; section > 0;
+       --section) {
+    if (![self.collectionViewModel numberOfItemsInSection:section]) {
+      [self.entryInserter removeSection:section];
+    }
+  }
+}
+
 - (void)filterForHistoryEntries:(NSArray*)entries {
   self.collectionView.allowsMultipleSelection = YES;
   for (int section = 1; section < [self.collectionViewModel numberOfSections];
@@ -665,7 +683,6 @@ const CGFloat kSeparatorInset = 10;
       }
     }
   }
-  [self removeSelectedItemsFromCollection];
 }
 
 - (void)addLoadingIndicator {