Suppress JavaScript dialogs when a tab puts itself into fullscreen.

chrome/browser/extensions/api/tab_capture/offscreen_tab.cc

 // 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.
 
 #include "chrome/browser/extensions/api/tab_capture/offscreen_tab.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/macros.h"
@@ skipping 112 matching lines @@
 
 void OffscreenTab::CloseContents(WebContents* source) {
   DCHECK_EQ(offscreen_tab_web_contents_.get(), source);
   // Javascript in the page called window.close().
   DVLOG(1) << "OffscreenTab will die at renderer's request for start_url="
            << start_url_.spec();
   owner_->DestroyTab(this);
   // |this| is no longer valid.
 }
 
-bool OffscreenTab::ShouldSuppressDialogs(WebContents* source) {
+bool OffscreenTab::ShouldSuppressDialogs(WebContents* source,
+                                         bool before_unload) {
   DCHECK_EQ(offscreen_tab_web_contents_.get(), source);
   // Suppress all because there is no possible direct user interaction with
   // dialogs.
   return true;
 }
 
 bool OffscreenTab::ShouldFocusLocationBarByDefault(WebContents* source) {
   DCHECK_EQ(offscreen_tab_web_contents_.get(), source);
   // Indicate the location bar should be focused instead of the page, even
   // though there is no location bar.  This will prevent the page from
@@ skipping 207 matching lines @@
 
   // Schedule the timer to check again in a second.
   capture_poll_timer_.Start(
       FROM_HERE,
       base::TimeDelta::FromSeconds(kPollIntervalInSeconds),
       base::Bind(&OffscreenTab::DieIfContentCaptureEnded,
                  base::Unretained(this)));
 }
 
 }  // namespace extensions