Add window open and close delegate methods to CWVUIDelegate.

ios/web_view/public/cwv_ui_delegate.h

Index: ios/web_view/public/cwv_ui_delegate.h
diff --git a/ios/web_view/public/cwv_ui_delegate.h b/ios/web_view/public/cwv_ui_delegate.h
index 0e3a5b9724b58335774605069d31aaa8919d22e5..c068a81af0be9b9c2e1afefe97148b9b6fd6a27a 100644
--- a/ios/web_view/public/cwv_ui_delegate.h
+++ b/ios/web_view/public/cwv_ui_delegate.h
@@ -10,12 +10,24 @@
 
 @class CWVHTMLElement;
 @class CWVWebView;
+@class CWVWebViewConfiguration;
+@class CWVNavigationAction;
 
 // UI delegate interface for a CWVWebView.  Embedders can implement the
 // functions in order to customize library behavior.
 @protocol CWVUIDelegate<NSObject>
 
 @optional
+// Instructs the delegate to create a new browsing window (f.e. in response to
+// window.open JavaScript call).

[Eugene But (OOO till 7-30), 2017/03/16 17:09:03]

Add to the comments: "Page will not open a window if this method returns nil or
not implemented. This method can not return |webView|."

[michaeldo, 2017/03/16 18:24:28]

Done.

+- (CWVWebView*)webView:(CWVWebView*)webView
+    createWebViewWithConfiguration:(CWVWebViewConfiguration*)configuration
+               forNavigationAction:(CWVNavigationAction*)action;
+
+// Instructs the delegate to close |webView|. Called only for windows opened by
+// DOM.
+- (void)webViewDidClose:(CWVWebView*)webView;
+
 // Instructs the delegate to present context menu in response to user’s long
 // press gesture at |location| in |view| coordinate space. |element| is an HTML
 // element which received the gesture.