Improves first run dialog performance on Win8

chrome/browser/ui/webui/set_as_default_browser_ui.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/webui/set_as_default_browser_ui.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 24 matching lines @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_ui.h"
 #include "content/public/browser/web_ui_data_source.h"
 #include "content/public/browser/web_ui_message_handler.h"
 #include "grit/browser_resources.h"
 #include "ui/base/l10n/l10n_font_util.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/font.h"
-#include "ui/views/widget/widget.h"
 #include "ui/web_dialogs/web_dialog_delegate.h"
 
 using content::BrowserThread;
 using content::WebContents;
 using content::WebUIMessageHandler;
 
 namespace {
 
 const char kSetAsDefaultBrowserHistogram[] = "DefaultBrowser.InteractionResult";
 
+views::Widget* g_dialog_widget;

[grt (UTC plus 2), 2016/07/13 08:54:49]

if you must use a global variable (i see you're discussing alternatives with
sky@), please:
- initialize it via " = nullptr;" here
- make sure it isn't already set via DCHECK_EQ(nullptr, ...); when initially set
- when the widget is closed, DCHECK_EQ(closing_widget, g_dialog_widget); (or
DCHECK_NE(nullptr, ...) if it's difficult to get the widget ptr at close time)
and set the global back to nullptr

also, i'd be inclined to make this a static member of
SetAsDefaultBrowserDialogImpl so that it's scoped nicely.

[zmin, 2016/07/18 21:12:14]

Done.
Done.
Done.
Done.

+
 // The enum permits registering in UMA the three possible outcomes (do not
 // reorder these).
 // ACCEPTED: user pressed Next and made Chrome default.
 // DECLINED: user simply closed the dialog without making Chrome default.
 // REGRETTED: user pressed Next but then elected a different default browser.
 enum MakeChromeDefaultResult {
   MAKE_CHROME_DEFAULT_ACCEPTED = 0,
   MAKE_CHROME_DEFAULT_DECLINED = 1,
   MAKE_CHROME_DEFAULT_REGRETTED = 2,
   // MAKE_CHROME_DEFAULT_ACCEPTED_IMMERSE = 3,  // Deprecated.
@@ skipping 173 matching lines @@
     BrowserList::RemoveObserver(this);
   if (owns_handler_)
     delete handler_;
 }
 
 void SetAsDefaultBrowserDialogImpl::ShowDialog() {
   // Use a NULL parent window to make sure that the dialog will have an item
   // in the Windows task bar. The code below will make it highlight if the
   // dialog is not in the foreground.
   gfx::NativeWindow native_window = chrome::ShowWebDialog(NULL, profile_, this);
-  views::Widget* widget = views::Widget::GetWidgetForNativeWindow(
-      native_window);
-  widget->FlashFrame(true);
+  g_dialog_widget = views::Widget::GetWidgetForNativeWindow(native_window);
+  g_dialog_widget->FlashFrame(true);
 }
 
 ui::ModalType SetAsDefaultBrowserDialogImpl::GetDialogModalType() const {
   return ui::MODAL_TYPE_SYSTEM;
 }
 
 base::string16 SetAsDefaultBrowserDialogImpl::GetDialogTitle() const {
   return l10n_util::GetStringUTF16(IDS_METRO_FLOW_TAB_TITLE);
 }
 
@@ skipping 83 matching lines @@
       Profile::FromWebUI(web_ui), CreateSetAsDefaultBrowserUIHTMLSource());
 }
 
 // static
 void SetAsDefaultBrowserUI::Show(Profile* profile, Browser* browser) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   SetAsDefaultBrowserDialogImpl* dialog =
       new SetAsDefaultBrowserDialogImpl(profile, browser);
   dialog->ShowDialog();
 }
+
+// static
+views::Widget* SetAsDefaultBrowserUI::GetDialogWidgetForTesting() {
+  return g_dialog_widget;
+}