Fix crash in echoPrivate.getUserConsent when there are no browser windows

chrome/browser/chromeos/extensions/echo_private_api.cc

 // Copyright (c) 2012 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/chromeos/extensions/echo_private_api.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/chromeos/ui/echo_dialog_view.h"
 #include "chrome/browser/ui/browser.h"
-#include "chrome/browser/ui/browser_window.h"
 #include "chrome/common/extensions/api/echo_private.h"
 #include "chrome/common/pref_names.h"
 #include "chromeos/system/statistics_provider.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/web_contents.h"
 #include "extensions/common/extension.h"
 
 namespace echo_api = extensions::api::echo_private;
 
 using content::BrowserThread;
 
 namespace {
 
 // URL of "More info" link shown in echo dialog in GetUserConsent function.
 const char kMoreInfoLink[] =
@@ skipping 195 matching lines @@
       echo_api::GetUserConsent::Params::Create(*args_);
 
   // Verify that the passed origin URL is valid.
   GURL service_origin = GURL(params->consent_requester.origin);
   if (!service_origin.is_valid()) {
     error_ = "Invalid origin.";
     SendResponse(false);
     return;
   }
 
+  content::WebContents* web_contents = GetAssociatedWebContents();
+  if (!web_contents) {
+    error_ = "No web contents.";
+    SendResponse(false);
+    return;
+  }
+
   // Add ref to ensure the function stays around until the dialog listener is
   // called. The reference is release in |Finalize|.
   AddRef();
 
   // Create and show the dialog.
   chromeos::EchoDialogView* dialog = new chromeos::EchoDialogView(this);
   if (redeem_offers_allowed_) {
     dialog->InitForEnabledEcho(
         base::UTF8ToUTF16(params->consent_requester.service_name),
         base::UTF8ToUTF16(params->consent_requester.origin));
   } else {
     dialog->InitForDisabledEcho();
   }
-  dialog->Show(GetCurrentBrowser()->window()->GetNativeWindow());
+  dialog->Show(web_contents->GetTopLevelNativeWindow());
 
   // If there is a dialog_shown_callback_, invoke it with the created dialog.
   if (!dialog_shown_callback_.is_null())
     dialog_shown_callback_.Run(dialog);
 }
 
 void EchoPrivateGetUserConsentFunction::Finalize(bool consent) {
   // Consent should not be true if offers redeeming is disabled.
   CHECK(redeem_offers_allowed_ || !consent);
   results_ = echo_api::GetUserConsent::Results::Create(consent);
   SendResponse(true);
 
   // Release the reference added in |OnRedeemOffersAllowedChecked|, before
   // showing the dialog.
   Release();
 }