Prevent unused-variable warnings in the CrOS build with gcc 4.6.

chrome/browser/chromeos/login/screen_locker_views.cc

 // 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.
 
 #include "chrome/browser/chromeos/login/screen_locker_views.h"
 
 #include <X11/extensions/XTest.h>
 #include <X11/keysym.h>
 #include <gdk/gdkkeysyms.h>
 #include <gdk/gdkx.h>
@@ skipping 778 matching lines @@
                                                    const string16& message) {
   postponed_error_message_ = message;
   if (captcha_view_) {
     captcha_view_->SetCaptchaURL(captcha_url);
   } else {
     captcha_view_ = new CaptchaView(captcha_url, true);
     captcha_view_->Init();
     captcha_view_->set_delegate(this);
   }
   // CaptchaView ownership is passed to grab_container_.
-  views::View* view = secondary_view_.release();
-  view = NULL;
+  ignore_result(secondary_view_.release());
   screen_lock_view_->SetVisible(false);
   grab_container_->SetScreenLockView(captcha_view_);
   background_container_->SetScreenLockView(captcha_view_);
   captcha_view_->SetVisible(true);
   // Take ScreenLockView ownership now that it's removed from grab_container_.
   secondary_view_.reset(screen_lock_view_);
 }
 
 void ScreenLockerViews::ClearErrors() {
   if (error_info_) {
@@ skipping 24 matching lines @@
 
 void ScreenLockerViews::OnCaptchaEntered(const std::string& captcha) {
   // Captcha dialog is only shown when LoginPerformer instance exists,
   // i.e. blocking UI after password change is in place.
   DCHECK(LoginPerformer::default_performer());
   LoginPerformer::default_performer()->set_captcha(captcha);
 
   // ScreenLockView ownership is passed to grab_container_.
   // Need to save return value here so that compile
   // doesn't fail with "unused result" warning.
-  views::View* view = secondary_view_.release();
-  view = NULL;
+  ignore_result(secondary_view_.release());
   captcha_view_->SetVisible(false);
   grab_container_->SetScreenLockView(screen_lock_view_);
   background_container_->SetScreenLockView(screen_lock_view_);
   screen_lock_view_->SetVisible(true);
   screen_lock_view_->ClearAndSetFocusToPassword();
 
   // Take CaptchaView ownership now that it's removed from grab_container_.
   secondary_view_.reset(captcha_view_);
   ShowErrorMessage(postponed_error_message_, false);
   postponed_error_message_.clear();
@@ skipping 68 matching lines @@
 #if defined(TOOLKIT_USES_GTK)
   WmIpc::Message msg;
   WmIpc::instance()->DecodeMessage(*event, &msg);
   if (msg.type() == WM_IPC_MESSAGE_CHROME_NOTIFY_SCREEN_REDRAWN_FOR_LOCK) {
     OnWindowManagerReady();
   }
 #endif
 }
 
 }  // namespace chromeos