Remove bare new from TabGroupsIPHControllerTest

Bug: None
Change-Id: Ib88ea119296aa359d03aad85a864bd203464fdcb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2308691
Commit-Queue: Peter Boström <pbos@chromium.org>
Commit-Queue: Collin Baker <collinbaker@chromium.org>
Auto-Submit: Peter Boström <pbos@chromium.org>
Reviewed-by: Collin Baker <collinbaker@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790118}

chrome/browser/ui/views/tabs/tab_groups_iph_controller_unittest.cc

@@ -35,7 +35,8 @@ class TabGroupsIPHControllerTest : public BrowserWithTestWindowTest {
     views::Widget::InitParams widget_params;
     widget_params.context = GetContext();
 
-    anchor_widget_ = std::unique_ptr<views::Widget>(new ChromeTestWidget);
+    anchor_widget_ =
+        views::UniqueWidgetPtr(std::make_unique<ChromeTestWidget>());
     anchor_widget_->Init(std::move(widget_params));
 
     mock_tracker_ =