Use ScopedTaskEnvironment instead of MessageLoopForUI in ViewsTestBase.

ui/views/controls/webview/webview_unittest.cc

Index: ui/views/controls/webview/webview_unittest.cc
diff --git a/ui/views/controls/webview/webview_unittest.cc b/ui/views/controls/webview/webview_unittest.cc
index 5436b2923203d07ae61a8e8cecffb19575b449d5..1d9b6173bd79f6dc4b7354a44d12d359745b1abb 100644
--- a/ui/views/controls/webview/webview_unittest.cc
+++ b/ui/views/controls/webview/webview_unittest.cc
@@ -10,12 +10,10 @@
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
-#include "base/message_loop/message_loop.h"
-#include "base/test/scoped_task_scheduler.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/test/test_browser_context.h"
-#include "content/public/test/test_browser_thread.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "content/public/test/web_contents_tester.h"
 #include "content/test/test_content_browser_client.h"
 #include "ui/events/event.h"
@@ -132,13 +130,7 @@ class WebViewTestWebContentsDelegate : public content::WebContentsDelegate {
 // Provides functionality to test a WebView.
 class WebViewUnitTest : public views::test::WidgetTest {
  public:
-  WebViewUnitTest()
-      : ui_thread_(content::BrowserThread::UI, base::MessageLoop::current()),
-        scoped_task_scheduler_(base::MessageLoop::current()),
-        file_blocking_thread_(content::BrowserThread::FILE_USER_BLOCKING,
-                              base::MessageLoop::current()),
-        io_thread_(content::BrowserThread::IO, base::MessageLoop::current()),
-        top_level_widget_(nullptr) {}
+  WebViewUnitTest() = default;
 
   ~WebViewUnitTest() override {}
 
@@ -185,15 +177,12 @@ class WebViewUnitTest : public views::test::WidgetTest {
   }
 
  private:
-  content::TestBrowserThread ui_thread_;
-  base::test::ScopedTaskScheduler scoped_task_scheduler_;
-  content::TestBrowserThread file_blocking_thread_;
-  content::TestBrowserThread io_thread_;
+  content::TestBrowserThreadBundle test_browser_thread_bundle_;
   std::unique_ptr<content::TestBrowserContext> browser_context_;
   content::TestContentBrowserClient test_browser_client_;
 
-  Widget* top_level_widget_;
-  WebView* web_view_;
+  Widget* top_level_widget_ = nullptr;
+  WebView* web_view_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(WebViewUnitTest);
 };