Suppress JavaScript dialogs when a tab puts itself into fullscreen.

chrome/browser/background/background_contents.h

 // Copyright (c) 2011 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 CHROME_BROWSER_BACKGROUND_BACKGROUND_CONTENTS_H_
 #define CHROME_BROWSER_BACKGROUND_BACKGROUND_CONTENTS_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 55 matching lines @@
   ~BackgroundContents() override;
 
   content::WebContents* web_contents() const { return web_contents_.get(); }
   virtual const GURL& GetURL() const;
 
   // Adds this BackgroundContents to the queue of RenderViews to create.
   void CreateRenderViewSoon(const GURL& url);
 
   // content::WebContentsDelegate implementation:
   void CloseContents(content::WebContents* source) override;
-  bool ShouldSuppressDialogs(content::WebContents* source) override;
+  bool ShouldSuppressDialogs(content::WebContents* source,
+                             bool before_unload) override;
   void DidNavigateMainFramePostCommit(content::WebContents* tab) override;
   void AddNewContents(content::WebContents* source,
                       content::WebContents* new_contents,
                       WindowOpenDisposition disposition,
                       const gfx::Rect& initial_rect,
                       bool user_gesture,
                       bool* was_blocked) override;
   bool IsNeverVisible(content::WebContents* web_contents) override;
 
   // content::WebContentsObserver implementation:
@@ skipping 42 matching lines @@
   BackgroundContents* contents;
 
   // The name of the parent frame for these contents.
   const std::string& frame_name;
 
   // The ID of the parent application (if any).
   const base::string16& application_id;
 };
 
 #endif  // CHROME_BROWSER_BACKGROUND_BACKGROUND_CONTENTS_H_