Implementing sign-in promo histograms for bookmark

ios/chrome/browser/ui/bookmarks/bookmark_collection_view.h

 // Copyright 2014 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_BOOKMARKS_BOOKMARK_COLLECTION_VIEW_H_
 #define IOS_CHROME_BROWSER_UI_BOOKMARKS_BOOKMARK_COLLECTION_VIEW_H_
 
 #import <UIKit/UIKit.h>
 
 #include <set>
 #include <vector>
 
 #import "ios/chrome/browser/ui/bookmarks/bookmark_collection_cells.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_home_primary_view.h"
 #include "ios/chrome/browser/ui/bookmarks/bookmark_model_bridge_observer.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_utils_ios.h"
 
 @class BookmarkCollectionView;
 class GURL;
 @protocol UrlLoader;
 
 namespace bookmarks {
 class BookmarkNode;
 }  // namespace bookmarks
+namespace user_prefs {
+class PrefRegistrySyncable;
+}  // namespace user_prefs
 
 @protocol BookmarkCollectionViewDelegate<NSObject>
 
 // This method tells the delegate to add the node and cell
 // to the list of those being edited.
 - (void)bookmarkCollectionView:(BookmarkCollectionView*)view
                           cell:(UICollectionViewCell*)cell
              addNodeForEditing:(const bookmarks::BookmarkNode*)node;
 
 // This method tells the delegate to remove the node and cell from the list of
@@ skipping 46 matching lines @@
 // * |applyContentPosition:|: Given a content position from portrait
 //       orientation, change the content offset of the collection view to match
 //       that position.
 // * |changeOrientation:|: Calls |updateCollectionView|.
 // * |setScrollsToTop:|: Applies |scrollsToTop| to the collection view.
 // * |setEditing:animated:|: This method updates the editing property, but has
 //       no other effect. Subclasses must provide the actual functionality.
 @interface BookmarkCollectionView
     : UIView<BookmarkHomePrimaryView, BookmarkModelBridgeObserver>
 
+// Registers the feature preferences.
++ (void)registerBrowserStatePrefs:(user_prefs::PrefRegistrySyncable*)registry;
+
 // Designated initializer.
 - (instancetype)initWithBrowserState:(ios::ChromeBrowserState*)browserState
                                frame:(CGRect)frame;
 
 // Callback whenever the collection view is scrolled.
 - (void)collectionViewScrolled;
 
 // Refreshes the entire view to reflect |folder|.
 - (void)resetFolder:(const bookmarks::BookmarkNode*)folder;
 
 // Called when something outside the view causes the promo state to change.
 - (void)promoStateChangedAnimated:(BOOL)animate;
 
 @property(nonatomic, assign, readonly) bookmarks::BookmarkModel* bookmarkModel;
 @property(nonatomic, weak, readonly) id<UrlLoader> loader;
 @property(nonatomic, assign, readonly) ios::ChromeBrowserState* browserState;
 @property(nonatomic, weak) id<BookmarkCollectionViewDelegate> delegate;
 @property(nonatomic, assign, readonly) const bookmarks::BookmarkNode* folder;
 
+// Called when the bookmark view becomes visible.
+- (void)wasShown;
+
+// Called when the bookmark view becomes hidden.
+- (void)wasHidden;
+
 #pragma mark - Editing
 
 @property(nonatomic, assign, readonly) BOOL editing;
 
 #pragma mark - Promo Cell
 
 // Return true if the section at the given index is a promo section.
 - (BOOL)isPromoSection:(NSInteger)section;
 - (BOOL)shouldShowPromoCell;
 - (BOOL)isPromoActive;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_BOOKMARKS_BOOKMARK_COLLECTION_VIEW_H_