[ios] Automatically fail any WebTest whose render process crashes.

ios/web/public/web_state/global_web_state_observer.h

 // Copyright 2015 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_PUBLIC_WEB_STATE_GLOBAL_WEB_STATE_OBSERVER_H_
 #define IOS_WEB_PUBLIC_WEB_STATE_GLOBAL_WEB_STATE_OBSERVER_H_
 
 #include <stddef.h>
 
 #include "base/macros.h"
@@ skipping 27 matching lines @@
   // Called when |web_state| has started loading a page.
   virtual void WebStateDidStartLoading(WebState* web_state) {}
 
   // Called when |web_state| has stopped loading a page.
   virtual void WebStateDidStopLoading(WebState* web_state) {}
 
   // Called when the current page is loaded in |web_state|.
   virtual void PageLoaded(WebState* web_state,
                           PageLoadCompletionStatus load_completion_status) {}
 
+  // Called when the web process is terminated (usually by crashing, though
+  // possibly by other means).
+  virtual void RenderProcessGone(WebState* web_state) {}
+
   // Called when |web_state| is being destroyed.
   virtual void WebStateDestroyed(WebState* web_state) {}
 
  protected:
   GlobalWebStateObserver();
   virtual ~GlobalWebStateObserver();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GlobalWebStateObserver);
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_WEB_STATE_GLOBAL_WEB_STATE_OBSERVER_H_