Add window open and close delegate methods to CWVUIDelegate.

ios/web_view/public/cwv_navigation_action.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_WEB_VIEW_PUBLIC_CWV_NAVIGATION_ACTION_H_
+#define IOS_WEB_VIEW_PUBLIC_CWV_NAVIGATION_ACTION_H_
+
+#import <Foundation/Foundation.h>
+
+// Encapsulates information about an action which caused a navigation.
+@interface CWVNavigationAction : NSObject
+
+// Destination request associated with the action.
+@property(nonatomic, copy, readonly, nonnull) NSURLRequest* request;
+// YES if the action was caused by a user action (e.g. link tap).
+@property(nonatomic, readonly, getter=isUserInitiated) BOOL userInitiated;
+
+@end
+
+#endif  // IOS_WEB_VIEW_PUBLIC_CWV_NAVIGATION_ACTION_H_