Upstream Chrome on iOS source code [4/11].

ios/chrome/browser/ui/collection_view/collection_view_controller.h

+// 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.
+
+#ifndef IOS_CHROME_BROWSER_UI_COLLECTION_VIEW_COLLECTION_VIEW_CONTROLLER_H_
+#define IOS_CHROME_BROWSER_UI_COLLECTION_VIEW_COLLECTION_VIEW_CONTROLLER_H_
+
+#import "ios/chrome/browser/ui/material_components/app_bar_presenting.h"
+#import "ios/third_party/material_components_ios/src/components/Collections/src/MaterialCollections.h"
+
+@class CollectionViewModel;
+
+typedef NS_ENUM(NSInteger, CollectionViewControllerStyle) {
+  // A simple collection view controller.
+  CollectionViewControllerStyleDefault,
+  // A collection view controller with an app bar.
+  CollectionViewControllerStyleAppBar,
+};
+
+// Chrome-specific Material Design collection view controller. With
+// CollectionViewControllerStyleAppBar, it features an app bar in the card
+// style.
+@interface CollectionViewController
+    : MDCCollectionViewController<AppBarPresenting>
+
+// The model of this controller.
+@property(nonatomic, readonly) CollectionViewModel* collectionViewModel;
+
+// Initializer with the desired style.
+- (instancetype)initWithStyle:(CollectionViewControllerStyle)style
+    NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithCollectionViewLayout:(UICollectionViewLayout*)layout
+    NS_UNAVAILABLE;
+- (instancetype)initWithNibName:(NSString*)nibNameOrNil
+                         bundle:(NSBundle*)nibBundleOrNil NS_UNAVAILABLE;
+- (instancetype)initWithCoder:(NSCoder*)aDecoder NS_UNAVAILABLE;
+- (instancetype)init NS_UNAVAILABLE;
+
+// Initializes the collection view model. Must be called by subclasses if they
+// override this method in order to get a clean collectionViewModel.
+- (void)loadModel NS_REQUIRES_SUPER;
+
+// Reconfigures the cells corresponding to the given |items| by calling
+// |configureCell:| on each cell.
+- (void)reconfigureCellsForItems:(NSArray*)items
+         inSectionWithIdentifier:(NSInteger)sectionIdentifier;
+
+#pragma mark MDCCollectionViewEditingDelegate
+
+// Updates the model with changes to the collection view items. Must be called
+// by subclasses if they override this method in order to maintain this
+// functionality.
+- (void)collectionView:(UICollectionView*)collectionView
+    willDeleteItemsAtIndexPaths:(NSArray*)indexPaths NS_REQUIRES_SUPER;
+
+// Updates the model with changes to the collection view item. Must be called
+// by subclasses if they override this method in order to maintain this
+// functionality.
+- (void)collectionView:(UICollectionView*)collectionView
+    willMoveItemAtIndexPath:(NSIndexPath*)indexPath
+                toIndexPath:(NSIndexPath*)newIndexPath NS_REQUIRES_SUPER;
+
+#pragma mark UIScrollViewDelegate
+
+// Updates the MDCFlexibleHeader with changes to the collection view scroll
+// state. Must be called by subclasses if they override this method in order to
+// maintain this functionality.
+- (void)scrollViewDidScroll:(UIScrollView*)scrollView NS_REQUIRES_SUPER;
+
+// Updates the MDCFlexibleHeader with changes to the collection view scroll
+// state. Must be called by subclasses if they override this method in order to
+// maintain this functionality.
+- (void)scrollViewDidEndDragging:(UIScrollView*)scrollView
+                  willDecelerate:(BOOL)decelerate NS_REQUIRES_SUPER;
+
+// Updates the MDCFlexibleHeader with changes to the collection view scroll
+// state. Must be called by subclasses if they override this method in order to
+// maintain this functionality.
+- (void)scrollViewDidEndDecelerating:(UIScrollView*)scrollView
+    NS_REQUIRES_SUPER;
+
+// Updates the MDCFlexibleHeader with changes to the collection view scroll
+// state. Must be called by subclasses if they override this method in order to
+// maintain this functionality.
+- (void)scrollViewWillEndDragging:(UIScrollView*)scrollView
+                     withVelocity:(CGPoint)velocity
+              targetContentOffset:(inout CGPoint*)targetContentOffset
+    NS_REQUIRES_SUPER;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_COLLECTION_VIEW_COLLECTION_VIEW_CONTROLLER_H_