Add public API for handling Javascript alerts and prompt.

ios/web/web_state/web_state_impl.h

 // Copyright 2013 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_WEB_STATE_IMPL_H_
 #define IOS_WEB_WEB_STATE_WEB_STATE_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/values.h"
 #include "ios/web/navigation/navigation_manager_delegate.h"
 #include "ios/web/navigation/navigation_manager_impl.h"
 #include "ios/web/net/request_tracker_impl.h"
+#import "ios/web/public/java_script_dialog_callback.h"
+#include "ios/web/public/java_script_dialog_type.h"
 #include "ios/web/public/web_state/web_state.h"
 #include "url/gurl.h"
 
 @protocol CRWRequestTrackerDelegate;
 @class CRWWebController;
 @protocol CRWWebViewProxy;
 @class NSURLRequest;
 @class NSURLResponse;
 
 namespace net {
@@ skipping 227 matching lines @@
   void ShowWebInterstitial(WebInterstitialImpl* interstitial);
 
   // Called to dismiss the currently-displayed transient content view.
   void ClearTransientContentView();
 
   // Notifies the delegate that the load progress was updated.
   void SendChangeLoadProgress(double progress);
   // Notifies the delegate that a context menu needs handling.
   bool HandleContextMenu(const ContextMenuParams& params);
 
+  // Notifies the delegate that a JavaScript dialog needs to be presented.
+  void RunJavaScriptDialog(const GURL& origin_url,
+                           JavaScriptDialogType java_script_dialog_type,
+                           NSString* message_text,
+                           NSString* default_prompt_text,
+                           const DialogClosedCallback& callback);
+
+  // Cancels all dialogs associated with this web_state.
+  void CancelActiveAndPendingDialogs();
+
   // NavigationManagerDelegate:
   void NavigateToPendingEntry() override;
   void LoadURLWithParams(const NavigationManager::WebLoadParams&) override;
   void OnNavigationItemsPruned(size_t pruned_item_count) override;
   void OnNavigationItemChanged() override;
   void OnNavigationItemCommitted(
       const LoadCommittedDetails& load_details) override;
   WebState* GetWebState() override;
 
  protected:
@@ skipping 79 matching lines @@
 
   // Mojo interface registry for this WebState.
   std::unique_ptr<shell::InterfaceRegistry> mojo_interface_registry_;
 
   DISALLOW_COPY_AND_ASSIGN(WebStateImpl);
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_WEB_STATE_WEB_STATE_IMPL_H_