[iOS Clean] Created OverlayService.

ios/clean/chrome/browser/ui/web_contents/overlays/web_overlay_coordinator.mm

+// 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.
+
+#import "ios/clean/chrome/browser/ui/web_contents/overlays/web_overlay_coordinator.h"
+
+#import "base/logging.h"
+#import "ios/clean/chrome/browser/ui/commands/web_overlay_commands.h"
+#import "ios/clean/chrome/browser/ui/web_contents/overlays/web_overlay_queue.h"
+#import "ios/shared/chrome/browser/ui/browser_list/browser.h"
+#import "ios/shared/chrome/browser/ui/coordinators/browser_coordinator+internal.h"
+#import "ios/web/public/web_state/web_state.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@interface WebOverlayCoordinator () {
+  // The WebState requesting this overlay.
+  web::WebState* _webState;
+}
+
+@end
+
+@implementation WebOverlayCoordinator
+
+- (instancetype)initWithWebState:(web::WebState*)webState {
+  DCHECK(webState);
+  if ((self = [super init]))

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

Prefer to have {} around the conditional block in an initializer, where it is
very likely that more code will be added and there's a good chance of
introducing a wacky bug.

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

Acknowledged.

+    _webState = webState;
+  return self;
+}
+
+#pragma mark - Public
+
+- (void)startOverlayingWebCoordinator:(BrowserCoordinator*)webCoordinator {
+  DCHECK([webCoordinator canAddOverlayCoordinator:self]);
+  [webCoordinator addOverlayCoordinator:self];
+  [self start];
+}
+
+- (void)cancelWebKitCompletion {
+  // Must be implemented in subclasses.
+}
+
+#pragma mark - BrowserCoordinator
+
+- (void)stop {
+  // Notify the WebOverlayQueue that this coordinator has stopped so that it can
+  // be dequeued.
+  WebOverlayQueue::FromWebState(_webState)->WebOverlayWasStopped(self);
+  // Notify the scheduler that the overlay has stopped.

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

Move this comment after [super stop].

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

Acknowledged.

+  [super stop];
+  id<WebOverlaySchedulerCommands> overlayDispatcher =
+      static_cast<id<WebOverlaySchedulerCommands>>(self.browser->dispatcher());
+  [overlayDispatcher webOverlayWasStoppedForWebState:_webState];
+  // Remove as the overlay for its parent.
+  [self.parentCoordinator removeOverlayCoordinator];
+}
+
+@end