Adds delegate method to process avatar image for current user (1/4)

This adds a delegate method to ContentSuggestionsHeaderViewControllerDelegate
protocol specify how user's avatar image would be processed.

New Tab Page uses this delegate method to add/update the avatar for the
current user's identity and display at the top right corner of NTP.

Bug: 961120
Change-Id: I19abd5eab02481214a605de4b6321aa9a22ea79f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1612091Reviewed-by: Peter Lee <pkl@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Peter Lee <pkl@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660608}

ios/chrome/browser/ui/content_suggestions/BUILD.gn

@@ -104,6 +104,7 @@ source_set("content_suggestions_ui") {
     "content_suggestions_view_controller.mm",
     "content_suggestions_view_controller_audience.h",
     "ntp_home_consumer.h",
+    "user_account_image_update_delegate.h",
   ]
   deps = [
     ":content_suggestions_constant",

ios/chrome/browser/ui/content_suggestions/content_suggestions_header_view_controller_delegate.h

@@ -7,6 +7,8 @@
 
 #import <UIKit/UIKit.h>
 
+@protocol UserAccountImageUpdateDelegate;
+
 // Delegate for the ContentSuggestionsHeaderViewController.
 @protocol ContentSuggestionsHeaderViewControllerDelegate
 
@@ -16,6 +18,10 @@
 // Returns whether the collection is scrolled to its top.
 - (BOOL)isScrolledToTop;
 
+// Register |imageUpdater| object as delegate to refresh UI when user account
+// avatar is changed.
+- (void)registerImageUpdater:(id<UserAccountImageUpdateDelegate>)imageUpdater;
+
 // Returns whether calls that may trigger a URL load are allowed, such as a
 // voice search or focusing the omnibox via the fakebox.
 // See: crbug.com/925304 for more context.  Remove this when ios/web supports

ios/chrome/browser/ui/content_suggestions/ntp_home_mediator.mm

@@ -33,6 +33,7 @@
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_view_controller_audience.h"
 #import "ios/chrome/browser/ui/content_suggestions/ntp_home_consumer.h"
 #import "ios/chrome/browser/ui/content_suggestions/ntp_home_metrics.h"
+#import "ios/chrome/browser/ui/content_suggestions/user_account_image_update_delegate.h"
 #import "ios/chrome/browser/ui/location_bar/location_bar_notification_names.h"
 #include "ios/chrome/browser/ui/ntp/metrics.h"
 #import "ios/chrome/browser/ui/ntp/new_tab_page_header_constants.h"
@@ -469,6 +470,9 @@ const char kNTPHelpURL[] =
   return self.suggestionsViewController.scrolledToTop;
 }
 
+- (void)registerImageUpdater:(id<UserAccountImageUpdateDelegate>)imageUpdater {
+}
+
 - (BOOL)ignoreLoadRequests {
   NewTabPageTabHelper* NTPHelper =
       NewTabPageTabHelper::FromWebState(self.webState);

ios/chrome/browser/ui/content_suggestions/user_account_image_update_delegate.h

+// Copyright 2019 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_CONTENT_SUGGESTIONS_USER_ACCOUNT_IMAGE_UPDATE_DELEGATE_H_
+#define IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_USER_ACCOUNT_IMAGE_UPDATE_DELEGATE_H_
+
+// Delegate protocol to update UI with current user account avatar.
+@protocol UserAccountImageUpdateDelegate
+
+// Updates current user account avatar with supplied image.
+- (void)updateAccountImage:(UIImage*)image;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_USER_ACCOUNT_IMAGE_UPDATE_DELEGATE_H_