Implementing sign-in promo histograms for bookmark

ios/chrome/browser/ui/authentication/signin_promo_view_mediator.h

 // Copyright 2017 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_AUTHENTICATION_SIGNIN_PROMO_VIEW_MEDIATOR_H_
 #define IOS_CHROME_BROWSER_UI_AUTHENTICATION_SIGNIN_PROMO_VIEW_MEDIATOR_H_
 
 #import <Foundation/Foundation.h>
 
 #import "ios/chrome/browser/ui/authentication/signin_promo_view.h"
 #import "ios/chrome/browser/ui/authentication/signin_promo_view_delegate.h"
 
 @class ChromeIdentity;
 @class SigninPromoViewConfigurator;
 @protocol SigninPromoViewConsumer;
 
+namespace ios {
+class ChromeBrowserState;
+}  // namespace ios
+
 // Class that monitors the available identities and creates
 // SigninPromoViewConfigurator. This class makes the link between the model and
 // the view. The consumer will receive notification if default identity is
 // changed or updated.
 @interface SigninPromoViewMediator : NSObject<SigninPromoViewDelegate>
 
 // Consumer to handle identity update notifications.
 @property(nonatomic, weak) id<SigninPromoViewConsumer> consumer;
 
 // Chrome identity used to configure the view in a warm state mode. Otherwise
 // contains nil.
 @property(nonatomic, readonly, strong) ChromeIdentity* defaultIdentity;
 
 // Access point used to send user action metrics.
 @property(nonatomic) signin_metrics::AccessPoint accessPoint;
 
+// Preference key to count how many time the sign-in promo view is seen. The
+// value should point to static storage.
+@property(nonatomic) const char* displayedCountPreferenceKey;
+// Preference key, set to true when the sign-in promo view is seen too much. The
+// value should point to static storage.
+@property(nonatomic) const char* alreadySeenSigninViewPreferenceKey;
+// Histogram name to count how many times the signin promo is implicitly
+// dismissed per impression. The value should point to static storage.
+@property(nonatomic) const char* dismissalCountHistogramName;
+// Histogram name to count how many times one of the "sign in" buttons is
+// clicked per impression. The value should point to static storage.
+@property(nonatomic) const char* countTilSigninHistogramName;
+// Histogram name to counts how many times the explicit "X"-to-close button is
+// clicked per impression. The value should point to static storage.
+@property(nonatomic) const char* countTilXHistogramName;
+
+// See -[SigninPromoViewMediator initWithBrowserState:].
+- (instancetype)init NS_UNAVAILABLE;
+
+// Initialises with browser state.
+- (instancetype)initWithBrowserState:(ios::ChromeBrowserState*)browserState
+    NS_DESIGNATED_INITIALIZER;
+
 - (SigninPromoViewConfigurator*)createConfigurator;
 
+// Increments the "shown" counter used for histograms. Called when the signin
+// promo view is visible
+- (void)signinPromoViewVisible;
+
+// Called when the sign-in promo view is hidden.
+- (void)signinPromoViewHidden;
+
+// Called when the sign-in promo view is dismissed.
+- (void)signinPromoViewDismissed;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_AUTHENTICATION_SIGNIN_PROMO_VIEW_MEDIATOR_H_