views: Extract Widget observer into its own header file.

chrome/browser/ui/views/accessibility/invert_bubble_view.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/ui/views/accessibility/invert_bubble_view.h"
 
 #include "chrome/browser/event_disposition.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/page_navigator.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/sys_color_change_listener.h"
 #include "ui/views/bubble/bubble_delegate.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/link.h"
 #include "ui/views/controls/link_listener.h"
 #include "ui/views/layout/grid_layout.h"
 #include "ui/views/layout/layout_constants.h"
+#include "ui/views/widget/widget.h"
 
 namespace {
 
 const char kHighContrastExtensionUrl[] = "https://chrome.google.com/webstore/detail/djcfdncoelnlbldjfhinnjlhdjlikmph";
 const char kDarkThemeSearchUrl[] = "https://chrome.google.com/webstore/search-themes/dark";
 const char kLearnMoreUrl[] = "https://groups.google.com/a/googleproductforums.com/d/topic/chrome/Xrco2HsXS-8/discussion";
 const int kBubbleWidth = 500;
 
 class InvertBubbleView : public views::BubbleDelegateView,
                          public views::LinkListener {
@@ skipping 128 matching lines @@
   if (gfx::IsInvertedColorScheme() &&
       !pref_service->GetBoolean(prefs::kInvertNotificationShown)) {
     pref_service->SetBoolean(prefs::kInvertNotificationShown, true);
     InvertBubbleView* delegate = new InvertBubbleView(browser, anchor_view);
     views::BubbleDelegateView::CreateBubble(delegate);
     delegate->StartFade(true);
   }
 }
 
 }  // namespace browser