Remove calls to deprecated MessageLoop methods on Windows and Linux.

chrome/browser/ui/panels/panel_browsertest.cc

Index: chrome/browser/ui/panels/panel_browsertest.cc
diff --git a/chrome/browser/ui/panels/panel_browsertest.cc b/chrome/browser/ui/panels/panel_browsertest.cc
index 954a9e5c9ed616794790fca796f495c652609ebb..75bd4f867d18b2512cd6ac55187e51bcc07e4852 100644
--- a/chrome/browser/ui/panels/panel_browsertest.cc
+++ b/chrome/browser/ui/panels/panel_browsertest.cc
@@ -882,6 +882,8 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest,
 }
 
 IN_PROC_BROWSER_TEST_F(PanelBrowserTest, ChangeAutoHideTaskBarThickness) {
+  ASSERT_TRUE(base::MessageLoopForUI::IsCurrent());
+
   PanelManager* manager = PanelManager::GetInstance();
   DockedPanelCollection* docked_collection = manager->docked_collection();
   int initial_starting_right_position =
@@ -920,7 +922,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, ChangeAutoHideTaskBarThickness) {
   mock_display_settings_provider()->SetDesktopBarThickness(
       DisplaySettingsProvider::DESKTOP_BAR_ALIGNED_RIGHT,
       right_bar_thickness);
-  base::MessageLoopForUI::current()->RunUntilIdle();
+  base::RunLoop().RunUntilIdle();
   EXPECT_EQ(initial_starting_right_position,
             docked_collection->StartingRightPosition());
   EXPECT_EQ(docked_collection->work_area().bottom() - bottom_bar_thickness,
@@ -939,7 +941,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, ChangeAutoHideTaskBarThickness) {
   mock_display_settings_provider()->SetDesktopBarThickness(
       DisplaySettingsProvider::DESKTOP_BAR_ALIGNED_RIGHT,
       right_bar_thickness);
-  base::MessageLoopForUI::current()->RunUntilIdle();
+  base::RunLoop().RunUntilIdle();
   EXPECT_EQ(docked_collection->StartingRightPosition(),
             initial_starting_right_position);
   EXPECT_EQ(docked_collection->work_area().bottom() - bottom_bar_thickness,