Remove generics for header and footer of CollectionViewModel

ios/chrome/browser/ui/collection_view/collection_view_model.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_MODEL_H_
 #define IOS_CHROME_BROWSER_UI_COLLECTION_VIEW_COLLECTION_VIEW_MODEL_H_
 
 #import <UIKit/UIKit.h>
 
 @class CollectionViewItem;
@@ skipping 67 matching lines @@
 // |index|.
 - (void)removeItemWithType:(NSInteger)itemType
     fromSectionWithIdentifier:(NSInteger)sectionIdentifier
                       atIndex:(NSUInteger)index;
 
 // Removes the section for |sectionIdentifier|. If there are still items left in
 // the section, they are removed.
 - (void)removeSectionWithIdentifier:(NSInteger)sectionIdentifier;
 
 // Sets the header item for the section with the given |sectionIdentifier|.
-- (void)setHeader:(ObjectType)header
+- (void)setHeader:(CollectionViewItem*)header
     forSectionWithIdentifier:(NSInteger)sectionIdentifier;
 
 // Sets the footer item for the section with the given |sectionIdentifier|.
-- (void)setFooter:(ObjectType)footer
+- (void)setFooter:(CollectionViewItem*)footer
     forSectionWithIdentifier:(NSInteger)sectionIdentifier;
 
 #pragma mark Query model coordinates from index paths
 
 // Returns the section identifier for the given section.
 - (NSInteger)sectionIdentifierForSection:(NSInteger)section;
 
 // Returns the item type for the given index path.
 - (NSInteger)itemTypeForIndexPath:(NSIndexPath*)indexPath;
 
 // Returns the index in item type for the given index path.
 // It corresponds to the index of the item at index path, among all the items if
 // the same type in the given section.
 // For example, let [A, B, B, B] a section, where A and B are item identifiers.
 // -indexInItemTypeForIndexPath:{0, 0} would return 0.
 // -indexInItemTypeForIndexPath:{0, 1} would return 0.
 // -indexInItemTypeForIndexPath:{0, 3} would return 2.
 - (NSUInteger)indexInItemTypeForIndexPath:(NSIndexPath*)indexPath;
 
 #pragma mark Query items from index paths
 
 // Returns whether there is an item at the given index path.
 - (BOOL)hasItemAtIndexPath:(NSIndexPath*)indexPath;
 
 // Returns the item at the given index path.
 - (ObjectType)itemAtIndexPath:(NSIndexPath*)indexPath;
 
 // Returns the header for the given |section|.
-- (ObjectType)headerForSection:(NSInteger)section;
+- (CollectionViewItem*)headerForSection:(NSInteger)section;
 
 // Returns the footer for the given |section|.
-- (ObjectType)footerForSection:(NSInteger)section;
+- (CollectionViewItem*)footerForSection:(NSInteger)section;
 
 // Returns an array of items in the section with the given identifier.
 - (NSArray<ObjectType>*)itemsInSectionWithIdentifier:
     (NSInteger)sectionIdentifier;
 
 // Returns the header for the section with the given |sectionIdentifier|.
-- (ObjectType)headerForSectionWithIdentifier:(NSInteger)sectionIdentifier;
+- (CollectionViewItem*)headerForSectionWithIdentifier:
+    (NSInteger)sectionIdentifier;
 
 // Returns the footer for the section with the given |sectionIdentifier|.
-- (ObjectType)footerForSectionWithIdentifier:(NSInteger)sectionIdentifier;
+- (CollectionViewItem*)footerForSectionWithIdentifier:
+    (NSInteger)sectionIdentifier;
 
 #pragma mark Query index paths from model coordinates
 
 // Returns whether there is a section at the given section identifier.
 - (BOOL)hasSectionForSectionIdentifier:(NSInteger)sectionIdentifier;
 
 // Returns the index path's section for the given section identifier.
 - (NSInteger)sectionForSectionIdentifier:(NSInteger)sectionIdentifier;
 
 // Returns whether there is an item of type |itemType| at the given
@@ skipping 33 matching lines @@
 
 // Returns the number of collection view sections.
 - (NSInteger)numberOfSections;
 
 // Returns the number of collection view items in the given section.
 - (NSInteger)numberOfItemsInSection:(NSInteger)section;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_COLLECTION_VIEW_COLLECTION_VIEW_MODEL_H_