Adds Compose Email Settings UI for deprecating Native App Launcher

ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.h

Index: ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.h
diff --git a/ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.h b/ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..ffef01015d216d284df139674c820524e6c72cb0
--- /dev/null
+++ b/ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.h
@@ -0,0 +1,26 @@
+// 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_SETTINGS_COMPOSE_EMAIL_HANDLER_COLLECTION_VIEW_CONTROLLER_H_
+#define _IOS_CHROME_BROWSER_UI_SETTINGS_COMPOSE_EMAIL_HANDLER_COLLECTION_VIEW_CONTROLLER_H_
+
+#import "ios/chrome/browser/ui/settings/settings_root_collection_view_controller.h"
+
+@class MailtoURLRewriter;
+
+// UI for Compose Email settings to specify which installed Mail client app to
+// use for handling mailto: URLs. There must be at least 2 Mail client apps
+// installed before this UI should be shwon because there is no need to make

[jif, 2017/05/11 17:44:12]

/shwon/shown/ :)

[pkl (ping after 24h if needed), 2017/05/11 21:20:45]

Done.

+// a choice if there is only 1 Mail client app.
+@interface ComposeEmailHandlerCollectionViewController
+    : SettingsRootCollectionViewController
+
+- (instancetype)initWithRewriter:(MailtoURLRewriter*)rewriter;
+
+- (instancetype)initWithStyle:(CollectionViewControllerStyle)style
+    NS_UNAVAILABLE;
+
+@end
+
+#endif  // _IOS_CHROME_BROWSER_UI_SETTINGS_COMPOSE_EMAIL_HANDLER_COLLECTION_VIEW_CONTROLLER_H_