[iOS] Update NTP Reading List a11y label to include unread article count

This CL updates ContentSuggestionsMostVisitedActionItem to support
custom a11y labels that differ from their titles, and adds a custom
label for the Reading List cell that states the number of unread
articles.

Bug: 862299
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I972b5996fb3398154f656b8ea056b9028d468af0
Reviewed-on: https://chromium-review.googlesource.com/1137027
Commit-Queue: Kurt Horimoto <kkhorimoto@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575860}

ios/chrome/app/strings/ios_strings.grd

@@ -573,6 +573,12 @@ locale.  The strings in this file are specific to iOS.
       <message name="IDS_IOS_CONTENT_SUGGESTIONS_READING_LIST" desc="The Reading List title on the new tab page [Length: 10em]">
         Reading List
       </message>
+      <message name="IDS_IOS_CONTENT_SUGGESTIONS_READING_LIST_ACCESSIBILITY_LABEL_ONE_UNREAD" desc="The accessibility label to use for the reading list content suggestion cell when there is only a single unread article [Length: unlimited]">
+        1 unread Reading List article.
+      </message>
+      <message name="IDS_IOS_CONTENT_SUGGESTIONS_READING_LIST_ACCESSIBILITY_LABEL" desc="The accessibility label to use for the reading list content suggestion cell when there are multiple unread articles [Length: unlimited]">
+        <ph name="UNREAD_COUNT">$1<ex>4</ex></ph> unread Reading List articles.
+      </message>
       <message name="IDS_IOS_CONTENT_SUGGESTIONS_RECENT_TABS" desc="The Recent Tabs title on the new tab page [Length: 10em]">
         Recent Tabs
       </message>

ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_most_visited_action_item.h

@@ -27,9 +27,13 @@ typedef NS_ENUM(NSInteger, ContentSuggestionsMostVisitedAction) {
 - (nonnull instancetype)initWithAction:
     (ContentSuggestionsMostVisitedAction)action;
 
-// Text for the title and the accessibility label of the cell.
+// Text for the title of the cell.
 @property(nonatomic, copy, nonnull) NSString* title;
 
+// The accessibility label of the cell.  If none is provided, self.title is used
+// as the label.
+@property(nonatomic, copy, nullable) NSString* accessibilityLabel;
+
 // The action type for this button.
 @property(nonatomic, assign) ContentSuggestionsMostVisitedAction action;
 

ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_most_visited_action_item.mm

@@ -4,6 +4,9 @@
 
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_most_visited_action_item.h"
 
+#include "base/logging.h"
+#include "base/strings/sys_string_conversions.h"
+#include "base/strings/utf_string_conversions.h"
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_most_visited_action_cell.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -19,6 +22,7 @@
 @synthesize metricsRecorded = _metricsRecorded;
 @synthesize suggestionIdentifier = _suggestionIdentifier;
 @synthesize title = _title;
+@synthesize accessibilityLabel = _accessibilityLabel;
 
 - (instancetype)initWithAction:(ContentSuggestionsMostVisitedAction)action {
   self = [super initWithType:0];
@@ -30,13 +34,30 @@
   return self;
 }
 
+#pragma mark - Accessors
+
+- (void)setTitle:(NSString*)title {
+  if ([_title isEqualToString:title])
+    return;
+  _title = title;
+  [self updateAccessibilityLabel];
+}
+
+- (void)setCount:(NSInteger)count {
+  if (_count == count)
+    return;
+  _count = count;
+  [self updateAccessibilityLabel];
+}
+
 #pragma mark - AccessibilityCustomAction
 
 - (void)configureCell:(ContentSuggestionsMostVisitedActionCell*)cell {
   [super configureCell:cell];
   cell.accessibilityCustomActions = nil;
   cell.titleLabel.text = self.title;
-  cell.accessibilityLabel = self.title;
+  cell.accessibilityLabel =
+      self.accessibilityLabel.length ? self.accessibilityLabel : self.title;
   cell.iconView.image = [self imageForAction:_action];
   if (self.count != 0) {
     cell.countLabel.text = [@(self.count) stringValue];
@@ -54,6 +75,7 @@
 
 #pragma mark - Private
 
+// Returns the title to use for a cell with |action|.
 - (NSString*)titleForAction:(ContentSuggestionsMostVisitedAction)action {
   switch (action) {
     case ContentSuggestionsMostVisitedActionBookmark:
@@ -67,6 +89,7 @@
   }
 }
 
+// Returns the image to use for a cell with |action|.
 - (UIImage*)imageForAction:(ContentSuggestionsMostVisitedAction)action {
   switch (action) {
     case ContentSuggestionsMostVisitedActionBookmark:
@@ -80,4 +103,30 @@
   }
 }
 
+// Updates self.accessibilityLabel based on the current property values.
+- (void)updateAccessibilityLabel {
+  // Resetting self.accessibilityLabel to nil will prompt self.title to be used
+  // as the default label.  This default value should be used if:
+  // - the cell is not for Reading List,
+  // - there are no unread articles in the reading list.
+  if (self.action != ContentSuggestionsMostVisitedActionReadingList ||
+      self.count <= 0) {
+    self.accessibilityLabel = nil;
+    return;
+  }
+
+  BOOL hasMultipleArticles = self.count > 1;
+  int messageID =
+      hasMultipleArticles
+          ? IDS_IOS_CONTENT_SUGGESTIONS_READING_LIST_ACCESSIBILITY_LABEL
+          : IDS_IOS_CONTENT_SUGGESTIONS_READING_LIST_ACCESSIBILITY_LABEL_ONE_UNREAD;
+  if (hasMultipleArticles) {
+    self.accessibilityLabel = l10n_util::GetNSStringF(
+        messageID, base::SysNSStringToUTF16([@(self.count) stringValue]));
+  } else {
+    self.accessibilityLabel = l10n_util::GetNSString(messageID);
+  }
+  DCHECK(self.accessibilityLabel.length);
+}
+
 @end