Upstream ios/web/web_state/ui support classes

ios/web/web_state/ui/crw_wk_web_view_crash_detector.h

Index: ios/web/web_state/ui/crw_wk_web_view_crash_detector.h
diff --git a/ios/web/web_state/ui/crw_wk_web_view_crash_detector.h b/ios/web/web_state/ui/crw_wk_web_view_crash_detector.h
new file mode 100644
index 0000000000000000000000000000000000000000..6db04fbffd7aa270e1628dc63e9f6f6b15cd84d1
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+++ b/ios/web/web_state/ui/crw_wk_web_view_crash_detector.h
@@ -0,0 +1,21 @@
+// 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_WEB_VIEW_CRASH_DETECTOR_H_
+#define IOS_WEB_WEB_STATE_UI_CRW_WK_WEB_VIEW_CRASH_DETECTOR_H_
+
+#import <WebKit/WebKit.h>
+
+#import "base/ios/block_types.h"
+
+// A watchdog which detects and reports WKWebView crashes.
+@interface CRWWKWebViewCrashDetector : NSObject
+
+// Designated initializer. |handler| will be called if |webView| has crashed.
+- (instancetype)initWithWebView:(WKWebView*)webView
+                   crashHandler:(ProceduralBlock)handler;
+
+@end
+
+#endif  // IOS_WEB_WEB_STATE_UI_CRW_WK_WEB_VIEW_CRASH_DETECTOR_H_