Adds Compose Email Settings UI for deprecating Native App Launcher

ios/chrome/browser/ui/settings/content_settings_collection_view_controller_unittest.mm

 // Copyright 2013 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.
 
 #import "ios/chrome/browser/ui/settings/content_settings_collection_view_controller.h"
 
 #include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
+#include "ios/chrome/browser/experimental_flags.h"
+#import "ios/chrome/browser/ui/collection_view/cells/collection_view_detail_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller_test.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ios/web/public/test/test_web_thread_bundle.h"
+#include "testing/gtest_mac.h"
+#include "ui/base/l10n/l10n_util.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 namespace {
 
 class ContentSettingsCollectionViewControllerTest
     : public CollectionViewControllerTest {
  protected:
@@ skipping 11 matching lines @@
  private:
   web::TestWebThreadBundle thread_bundle_;
   std::unique_ptr<TestChromeBrowserState> chrome_browser_state_;
 };
 
 TEST_F(ContentSettingsCollectionViewControllerTest, TestModel) {
   CreateController();
   CheckController();
   CheckTitleWithId(IDS_IOS_CONTENT_SETTINGS_TITLE);
 
-  int expectedNumberOfItems = 2;
   ASSERT_EQ(1, NumberOfSections());
+  // Compose Email section is shown only if experiment is turned on and
+  // there are enough number of available mailto: URL handlers.
+  int number_of_handlers =
+      [[[[MailtoURLRewriter alloc] initWithStandardHandlers] defaultHandlers]
+          count];
+  bool show_compose_email_section =
+      experimental_flags::IsNativeAppLauncherEnabled() &&
+      number_of_handlers > 1;
+  int expectedNumberOfItems = show_compose_email_section ? 3 : 2;
   EXPECT_EQ(expectedNumberOfItems, NumberOfItemsInSection(0));
   CheckDetailItemTextWithIds(IDS_IOS_BLOCK_POPUPS, IDS_IOS_SETTING_ON, 0, 0);
   CheckDetailItemTextWithIds(IDS_IOS_TRANSLATE_SETTING, IDS_IOS_SETTING_ON, 0,
                              1);
+  if (show_compose_email_section) {
+    CollectionViewDetailItem* item = GetCollectionViewItem(0, 2);
+    EXPECT_NSEQ(l10n_util::GetNSString(IDS_IOS_COMPOSE_EMAIL_SETTING),
+                item.text);
+  }
 }
 
 }  // namespace