Upstream ios/web/web_state/ui support classes

ios/web/web_state/ui/crw_wk_script_message_router.h

+// Copyright 2014 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_WEB_STATE_UI_CRW_WK_SCRIPT_MESSAGE_ROUTER_H_

[Eugene But (OOO till 7-30), 2015/03/30 05:03:58]

Optional: I think I can remove this class at all very soon. Could you please
exclude if from this patch to avoid unnecessary churn.

[stuartmorgan, 2015/03/30 14:17:57]

Done.

+#define IOS_WEB_WEB_STATE_UI_CRW_WK_SCRIPT_MESSAGE_ROUTER_H_
+
+#import <WebKit/WebKit.h>
+
+// WKUserContentController wrapper that allows adding multiple message handlers
+// for the same message name. CRWWKScriptMessageRouter will route the messages
+// from the underlying user content controller to a designated reciever by
+// matching the message's name and webView.
+@interface CRWWKScriptMessageRouter : NSObject
+
+// Underlying WKUserContentController.
+@property(nonatomic, readonly) WKUserContentController* userContentController;
+
+// Designated initializer. |userContentController| must not be nil.
+- (instancetype)initWithUserContentController:
+    (WKUserContentController*)userContentController;
+
+// Sets a script message handler. Multiple message handlers can be added for
+// the same message name and long as |webView| are different. Setting |handler|
+// for the same |name| and |webView| pair is an error. |handler| will be called
+// if WKScriptMessage sent by WKUserContentController will match both the |name|
+// and the |webView|.
+- (void)setScriptMessageHandler:(void(^)(WKScriptMessage*))handler
+                           name:(NSString*)messageName
+                        webView:(WKWebView*)webView;
+
+// Removes a specific message handler.
+- (void)removeScriptMessageHandlerForName:(NSString*)messageName
+                                  webView:(WKWebView*)webView;
+
+// Removes all message handlers for the given |webView|.
+- (void)removeAllScriptMessageHandlersForWebView:(WKWebView*)webView;
+
+@end
+
+#endif  // IOS_WEB_WEB_STATE_UI_CRW_WK_SCRIPT_MESSAGE_ROUTER_H_