[Merge to 2840] Fix a bug where inactive windows would inappropriately take focus.

chrome/test/base/web_ui_browser_test.cc

Index: chrome/test/base/web_ui_browser_test.cc
diff --git a/chrome/test/base/web_ui_browser_test.cc b/chrome/test/base/web_ui_browser_test.cc
index 5dd111115f0265efbb10e82bce7cccf93195bc04..c0135cfe4ca33b23c90b87c7256c0d975b229e6c 100644
--- a/chrome/test/base/web_ui_browser_test.cc
+++ b/chrome/test/base/web_ui_browser_test.cc
@@ -222,6 +222,17 @@ void WebUIBrowserTest::BrowsePreload(const GURL& browse_to) {
   chrome::NavigateParams params(
       browser(), GURL(browse_to), ui::PAGE_TRANSITION_TYPED);
   params.disposition = CURRENT_TAB;
+
+  // This is needed to make the test
+  // MaterialHistoryBrowserTest.HistoryToolbarFocusTest pass on macOS. The test
+  // is fundamentally flawed, since it expects a particular widget to be
+  // focused. Chrome focus semantics are based on the Windows platform, where a
+  // widget cannot be focused without window activation. browser_tests can be
+  // sharded, so there is no way to enforce that a given window is activated.
+  // Focus tests should be interactive_ui_tests, and they should explicitly
+  // activate the window. https://crbug.com/642467.
+  params.window_action = chrome::NavigateParams::SHOW_WINDOW;
+
   chrome::Navigate(&params);
   navigation_observer.Wait();
 }