Remove all ReadingList entries on managed account signout.

ios/chrome/browser/signin/browser_state_data_remover.mm

Index: ios/chrome/browser/signin/browser_state_data_remover.mm
diff --git a/ios/chrome/browser/signin/browser_state_data_remover.mm b/ios/chrome/browser/signin/browser_state_data_remover.mm
index 40f2a359a0771901f0a8c28c9fa6d9bc2ea4c792..9c05d7c4444ae063ca175d7928f2d4fe4a01774a 100644
--- a/ios/chrome/browser/signin/browser_state_data_remover.mm
+++ b/ios/chrome/browser/signin/browser_state_data_remover.mm
@@ -10,6 +10,7 @@
 #include "components/signin/core/common/signin_pref_names.h"
 #include "ios/chrome/browser/bookmarks/bookmarks_utils.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#include "ios/chrome/browser/reading_list/reading_list_remover_helper.h"
 #import "ios/chrome/browser/ui/commands/UIKit+ChromeExecuteCommand.h"
 #import "ios/chrome/browser/ui/commands/clear_browsing_data_command.h"
 
@@ -66,6 +67,18 @@ void BrowserStateDataRemover::NotifyWithDetails(
   // there should be no issue calling the function here.
   CHECK(RemoveAllUserBookmarksIOS(browser_state_))
       << "Failed to remove all user bookmarks.";
+  reading_list_remover_helper_ =
+      base::MakeUnique<reading_list::ReadingListRemoverHelper>(browser_state_);
+  reading_list_remover_helper_->RemoveAllUserReadingListItemsIOS(
+      base::Bind(&BrowserStateDataRemover::ReadingListCleaned,
+                 base::Unretained(this), details));
+}
+
+void BrowserStateDataRemover::ReadingListCleaned(
+    const IOSChromeBrowsingDataRemover::NotificationDetails& details,
+    bool reading_list_cleaned) {
+  CHECK(reading_list_cleaned)
+      << "Failed to remove all user reading list items.";
 
   if (details.removal_mask != kRemoveAllDataMask) {
     NOTREACHED() << "Unexpected partial remove browsing data request "