[ios] Active web state observer in tab collection.

ios/clean/chrome/browser/ui/tab_collection/tab_collection_view_controller.mm

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/clean/chrome/browser/ui/tab_collection/tab_collection_view_controller.h"
 
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "base/strings/sys_string_conversions.h"
 #import "ios/clean/chrome/browser/ui/tab_collection/tab_collection_item.h"
@@ skipping 31 matching lines @@
   self.tabs.delegate = self;
   [self.tabs registerClass:[TabCollectionTabCell class]
       forCellWithReuseIdentifier:[TabCollectionTabCell identifier]];
 
   [NSLayoutConstraint activateConstraints:@[
     [self.tabs.topAnchor constraintEqualToAnchor:self.view.topAnchor],
     [self.tabs.bottomAnchor constraintEqualToAnchor:self.view.bottomAnchor],
     [self.tabs.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor],
     [self.tabs.trailingAnchor constraintEqualToAnchor:self.view.trailingAnchor],
   ]];
-
-  [self selectItemAtIndex:self.selectedIndex];
 }
 
 - (UIStatusBarStyle)preferredStatusBarStyle {
   return UIStatusBarStyleLightContent;
 }
 
 #pragma mark - Required subclass override
 
 - (UICollectionViewLayout*)collectionViewLayout {
   NOTREACHED() << "You must override "
@@ skipping 33 matching lines @@
           dequeueReusableCellWithReuseIdentifier:[TabCollectionTabCell
                                                      identifier]
                                     forIndexPath:indexPath]);
   cell.delegate = self;
   [cell setSessionType:TabSwitcherSessionType::REGULAR_SESSION];
   DCHECK_LE(indexPath.item, INT_MAX);
   int index = static_cast<int>(indexPath.item);
   [cell setAppearanceForTabTitle:self.items[index].title
                          favicon:nil
                         cellSize:CGSizeZero];
+  [cell setSelected:(index == self.selectedIndex)];
   return cell;
 }
 
 #pragma mark - UICollectionViewDelegate methods
 
 - (BOOL)collectionView:(UICollectionView*)collectionView
     shouldSelectItemAtIndexPath:(NSIndexPath*)indexPath {
   // Prevent user selection of items.
   return NO;
 }
@@ skipping 14 matching lines @@
 
 - (void)deleteButtonPressedForCell:(UICollectionViewCell*)cell {
   NSInteger item = [[self.tabs indexPathForCell:cell] item];
   DCHECK_LE(item, INT_MAX);
   int index = static_cast<int>(item);
   [self closeTabAtIndex:index];
 }
 
 #pragma mark - TabCollectionConsumer methods
 
-- (void)insertItem:(TabCollectionItem*)item atIndex:(int)index {
+- (void)insertItem:(TabCollectionItem*)item
+           atIndex:(int)index
+     selectedIndex:(int)selectedIndex {
+  DCHECK_GE(index, 0);
   DCHECK_LE(static_cast<NSUInteger>(index), self.items.count);
   [self.items insertObject:item atIndex:index];
   [self.tabs insertItemsAtIndexPaths:@[ [self indexPathForIndex:index] ]];
+  [self selectItemAtIndex:selectedIndex];

[marq (ping after 24h), 2017/05/30 11:09:43]

I think I don't like the view controller calling consumer methods on itself. I'd
rather have (say) a custom setter for selectedIndex that does the work currently
in -selectItemAtIndex.

[edchin, 2017/06/01 23:52:28]

Good idea. Done.

 }
 
-- (void)deleteItemAtIndex:(int)index {
+- (void)deleteItemAtIndex:(int)index selectedIndex:(int)selectedIndex {
+  DCHECK_GE(index, 0);
   DCHECK_LT(static_cast<NSUInteger>(index), self.items.count);
   [self.items removeObjectAtIndex:index];
   [self.tabs deleteItemsAtIndexPaths:@[ [self indexPathForIndex:index] ]];
+  [self selectItemAtIndex:selectedIndex];
 }
 
-- (void)moveItemFromIndex:(int)fromIndex toIndex:(int)toIndex {
+- (void)moveItemFromIndex:(int)fromIndex
+                  toIndex:(int)toIndex
+            selectedIndex:(int)selectedIndex {
   TabCollectionItem* item = self.items[fromIndex];
   [self.items removeObjectAtIndex:fromIndex];
   [self.items insertObject:item atIndex:toIndex];
   [self.tabs moveItemAtIndexPath:[self indexPathForIndex:fromIndex]
                      toIndexPath:[self indexPathForIndex:toIndex]];
+  [self selectItemAtIndex:selectedIndex];
 }
 
 - (void)replaceItemAtIndex:(int)index withItem:(TabCollectionItem*)item {
-  [self.items removeObjectAtIndex:index];
-  [self.items insertObject:item atIndex:index];
+  DCHECK_GE(index, 0);
+  DCHECK_LT(static_cast<NSUInteger>(index), self.items.count);
+  self.items[index] = item;
+  [self.tabs reloadItemsAtIndexPaths:@[ [self indexPathForIndex:index] ]];
 }
 
 - (void)selectItemAtIndex:(int)index {
+  NSMutableArray* indexPaths = [[NSMutableArray alloc] init];
+  if (self.selectedIndex >= 0 &&
+      static_cast<NSUInteger>(self.selectedIndex) < self.items.count) {
+    [indexPaths addObject:[self indexPathForIndex:self.selectedIndex]];
+  }
+  if (index >= 0 && self.selectedIndex != index) {
+    DCHECK_LT(static_cast<NSUInteger>(index), self.items.count);
+    [indexPaths addObject:[self indexPathForIndex:index]];
+  }
   self.selectedIndex = index;
-  [self.tabs selectItemAtIndexPath:[self indexPathForIndex:index]
-                          animated:YES
-                    scrollPosition:UITableViewScrollPositionNone];
+  [self.tabs reloadItemsAtIndexPaths:indexPaths];

[marq (ping after 24h), 2017/05/30 11:09:44]

Should this use -selectItemsAtIndexPath:animated:scrollPosition: and
deselectItemAtIndexPath:animated: instead of reloading the items?

[edchin, 2017/06/01 23:52:29]

Yes, selection should be done on the collection view rather than on cells.
This is now updated to work properly.

 }
 
-- (void)populateItems:(NSArray<TabCollectionItem*>*)items {
+- (void)populateItems:(NSArray<TabCollectionItem*>*)items
+        selectedIndex:(int)selectedIndex {
   self.items = [items mutableCopy];
+  self.selectedIndex = selectedIndex;
   [self.tabs reloadData];
 }
 
 #pragma mark - Private
 
 - (NSIndexPath*)indexPathForIndex:(int)index {

[marq (ping after 24h), 2017/05/30 11:09:44]

Does this helper method pull its weight? 

[edchin, 2017/06/01 23:52:29]

Removed.

   return [NSIndexPath indexPathForItem:index inSection:0];
 }
 
 @end