[iOS Clean] Created OverlayService.

ios/clean/chrome/browser/ui/commands/web_overlay_commands.h

+// 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_CLEAN_CHROME_BROWSER_UI_COMMANDS_WEB_OVERLAY_COMMANDS_H_
+#define IOS_CLEAN_CHROME_BROWSER_UI_COMMANDS_WEB_OVERLAY_COMMANDS_H_
+
+#import <Foundation/Foundation.h>
+
+namespace web {
+class WebState;
+}
+
+@class WebOverlayCoordinator;

[marq (ping after 24h), 2017/06/02 16:14:11]

Not needed -- this should be a red flag for a command protocol, which should
only depend on (at most) model classes.

[kkhorimoto, 2017/06/03 00:37:32]

Removed.  This was leftover from a previous command that I didn't end up using.

+
+// Commands used to schedule overlay coordinators requested by web pages.
+@protocol WebOverlaySchedulerCommands<NSObject>
+// Notifies the scheduler that |webState| has a queued overlay coordinator to
+// display.
+- (void)scheduleWebOverlayForWebState:(web::WebState*)webState;
+// Notifies the scheduler that the overlay that was started over |webState|'s
+// content area has been stopped.
+- (void)webOverlayWasStoppedForWebState:(web::WebState*)webState;
+// Notifies the scheduler to cancel all overlays scheduled for |webState|.
+- (void)cancelWebOverlaysForWebState:(web::WebState*)webState;
+@end
+
+// Commands used by the scheduler to start queued WebOverlayCoordinators.
+@protocol WebOverlayPresentationCommands<NSObject>
+// Called by the scheduler to notify the coordinator showing the web content to
+// start its next queued overlay.
+- (void)startNextWebOverlayForWebState:(web::WebState*)webState;
+@end
+
+#endif  // IOS_CLEAN_CHROME_BROWSER_UI_COMMANDS_WEB_OVERLAY_COMMANDS_H_