[tab_grid] New collection view layout.

ios/clean/chrome/browser/ui/tab_grid/tab_grid_view_controller.mm

 // Copyright 2016 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.
 
 // ======                        New Architecture                         =====
 // =         This code is only used in the new iOS Chrome architecture.       =
 // ============================================================================
 
 #import "ios/clean/chrome/browser/ui/tab_grid/tab_grid_view_controller.h"
 
 #include "base/mac/foundation_util.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_panel_cell.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_panel_collection_view_layout.h"
 #import "ios/clean/chrome/browser/ui/actions/settings_actions.h"
 #import "ios/clean/chrome/browser/ui/actions/tab_grid_actions.h"
 #import "ios/clean/chrome/browser/ui/commands/settings_commands.h"
 #import "ios/clean/chrome/browser/ui/commands/tab_commands.h"
 #import "ios/clean/chrome/browser/ui/commands/tab_grid_commands.h"
 #import "ios/clean/chrome/browser/ui/tab_grid/mdc_floating_button+cr_tab_grid.h"
+#import "ios/clean/chrome/browser/ui/tab_grid/tab_grid_collection_view_layout.h"
 #import "ios/clean/chrome/browser/ui/tab_grid/ui_stack_view+cr_tab_grid.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 namespace {
-const CGFloat kSpace = 20.0f;
-const CGFloat kTabSize = 150.0f;
 // Height of toolbar in tab grid.
 const CGFloat kToolbarHeight = 64.0f;
 }
 
 @interface TabGridViewController ()<SettingsActions,
                                     TabGridActions,
                                     UICollectionViewDataSource,
                                     UICollectionViewDelegate,
                                     SessionCellDelegate>
 @property(nonatomic, weak) UICollectionView* grid;
@@ skipping 14 matching lines @@
   [self.view addSubview:toolbar];
 
   toolbar.translatesAutoresizingMaskIntoConstraints = NO;
   [NSLayoutConstraint activateConstraints:@[
     [toolbar.heightAnchor constraintEqualToConstant:kToolbarHeight],
     [toolbar.widthAnchor constraintEqualToAnchor:self.view.widthAnchor],
     [toolbar.topAnchor constraintEqualToAnchor:self.view.topAnchor],
     [toolbar.centerXAnchor constraintEqualToAnchor:self.view.centerXAnchor]
   ]];
 
-  TabSwitcherPanelCollectionViewLayout* layout =
-      [[TabSwitcherPanelCollectionViewLayout alloc] init];
-  layout.minimumLineSpacing = kSpace;
-  layout.minimumInteritemSpacing = kSpace;
-  layout.sectionInset = UIEdgeInsetsMake(kSpace, kSpace, kSpace, kSpace);
-  layout.itemSize = CGSizeMake(kTabSize, kTabSize);
-
+  TabGridCollectionViewLayout* layout =
+      [[TabGridCollectionViewLayout alloc] init];
   UICollectionView* grid = [[UICollectionView alloc] initWithFrame:CGRectZero
                                               collectionViewLayout:layout];
   grid.translatesAutoresizingMaskIntoConstraints = NO;
   grid.backgroundColor = [UIColor blackColor];
 
   [self.view addSubview:grid];
   self.grid = grid;
   self.grid.dataSource = self;
   self.grid.delegate = self;
   [self.grid registerClass:[TabSwitcherLocalSessionCell class]
@@ skipping 79 matching lines @@
 - (void)deleteButtonPressedForCell:(UICollectionViewCell*)cell {
   auto updateBlock = ^{
     NSIndexPath* indexPath = [self.grid indexPathForCell:cell];
     [self.tabCommandHandler closeTabAtIndexPath:indexPath];
     [self.grid deleteItemsAtIndexPaths:@[ indexPath ]];
   };
   [self.grid performBatchUpdates:updateBlock completion:nil];
 }
 
 @end