Upstream Chrome on iOS source code [9/11].

ios/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/chrome/browser/ui/tab_grid/tab_grid_view_controller.h"
+
+#include "base/mac/foundation_util.h"
+#import "ios/chrome/browser/ui/actions/settings_actions.h"
+#import "ios/chrome/browser/ui/actions/tab_grid_actions.h"
+#import "ios/chrome/browser/ui/tab_grid/tab_grid_tab_cell.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace {
+NSString* const kTabGridCellIdentifier = @"tabGridCell";
+const CGFloat kSpace = 20;
+const CGFloat kTabSize = 150;
+}
+
+@interface TabGridViewController ()<SettingsActions,
+                                    TabGridActions,
+                                    UICollectionViewDataSource,
+                                    UICollectionViewDelegate>
+@property(nonatomic, weak) UICollectionView* grid;
+@end
+
+@implementation TabGridViewController
+
+@synthesize dataSource = _dataSource;
+@synthesize actionDelegate = _actionDelegate;
+@synthesize grid = _grid;
+
+- (void)viewDidLoad {
+  // Placeholder dark grey stripe at the top of the view.
+  UIView* stripe = [[UIView alloc] initWithFrame:CGRectZero];
+  stripe.translatesAutoresizingMaskIntoConstraints = NO;
+  stripe.backgroundColor = [UIColor darkGrayColor];
+  [self.view addSubview:stripe];
+
+  // Placeholder settings button at in the stripe.
+  UIButton* settings = [UIButton buttonWithType:UIButtonTypeSystem];
+  settings.translatesAutoresizingMaskIntoConstraints = NO;
+  [settings setTitle:@"⚙" forState:UIControlStateNormal];
+  settings.titleLabel.font = [UIFont systemFontOfSize:24.0];
+  [settings addTarget:nil
+                action:@selector(showSettings:)
+      forControlEvents:UIControlEventTouchUpInside];
+  [stripe addSubview:settings];
+
+  [NSLayoutConstraint activateConstraints:@[
+    [stripe.heightAnchor constraintEqualToConstant:64.0],
+    [stripe.widthAnchor constraintEqualToAnchor:self.view.widthAnchor],
+    [stripe.topAnchor constraintEqualToAnchor:self.view.topAnchor],
+    [stripe.centerXAnchor constraintEqualToAnchor:self.view.centerXAnchor],
+    [settings.leadingAnchor
+        constraintEqualToAnchor:stripe.layoutMarginsGuide.leadingAnchor],
+    [settings.centerYAnchor constraintEqualToAnchor:stripe.centerYAnchor]
+  ]];
+
+  UICollectionViewFlowLayout* layout =
+      [[UICollectionViewFlowLayout alloc] init];
+  layout.minimumLineSpacing = kSpace;
+  layout.minimumInteritemSpacing = kSpace;
+  layout.sectionInset = UIEdgeInsetsMake(kSpace, kSpace, kSpace, kSpace);
+  layout.itemSize = CGSizeMake(kTabSize, kTabSize);
+
+  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:[TabGridTabCell class]
+      forCellWithReuseIdentifier:kTabGridCellIdentifier];
+
+  [NSLayoutConstraint activateConstraints:@[
+    [self.grid.topAnchor constraintEqualToAnchor:stripe.bottomAnchor],
+    [self.grid.bottomAnchor constraintEqualToAnchor:self.view.bottomAnchor],
+    [self.grid.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor],
+    [self.grid.trailingAnchor constraintEqualToAnchor:self.view.trailingAnchor],
+  ]];
+}
+
+- (void)viewWillAppear:(BOOL)animated {
+  [self.grid reloadData];
+}
+
+#pragma mark - UICollectionViewDataSource methods
+
+- (NSInteger)numberOfSectionsInCollectionView:
+    (UICollectionView*)collectionView {
+  return 1;
+}
+
+- (NSInteger)collectionView:(UICollectionView*)collectionView
+     numberOfItemsInSection:(NSInteger)section {
+  return [self.dataSource numberOfTabsInTabGrid];
+}
+
+- (UICollectionViewCell*)collectionView:(UICollectionView*)collectionView
+                 cellForItemAtIndexPath:(nonnull NSIndexPath*)indexPath {
+  TabGridTabCell* cell =
+      base::mac::ObjCCastStrict<TabGridTabCell>([collectionView
+          dequeueReusableCellWithReuseIdentifier:kTabGridCellIdentifier
+                                    forIndexPath:indexPath]);
+  cell.contentView.backgroundColor = [UIColor purpleColor];
+  cell.selected = YES;
+  cell.label.text = [self.dataSource titleAtIndex:indexPath.item];
+  return cell;
+}
+
+#pragma mark - UICollectionViewDelegate methods
+
+- (void)collectionView:(UICollectionView*)collectionView
+    didSelectItemAtIndexPath:(NSIndexPath*)indexPath {
+  [self.actionDelegate showTabAtIndexPath:indexPath];
+}
+
+#pragma mark - ZoomTransitionDelegate methods
+
+- (CGRect)rectForZoomWithKey:(NSObject*)key inView:(UIView*)view {
+  NSIndexPath* cellPath = base::mac::ObjCCastStrict<NSIndexPath>(key);
+  if (!key)
+    return CGRectNull;
+  UICollectionViewCell* cell = [self.grid cellForItemAtIndexPath:cellPath];
+  return [view convertRect:cell.bounds fromView:cell];
+}
+
+#pragma mark - SettingsActions
+
+- (void)showSettings:(id)sender {
+  [self.actionDelegate showSettings];
+}
+
+#pragma mark - TabGridActions
+
+- (void)showTabGrid:(id)sender {
+  [self.actionDelegate showTabGrid];
+}
+
+@end