Disable renderer backgrounding in Chrome Navigation Browser Test

This was timing out with the Mac renderer backgrounding experiment on
since it was taking too long for the backgrounded tab to wake up and
execute the necessary commands.

BUG=460102

Review-Url: https://codereview.chromium.org/2626293002
Cr-Commit-Position: refs/heads/master@{#443438}

chrome/browser/chrome_navigation_browsertest.cc

@@ -17,6 +17,7 @@
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents_observer.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/common/context_menu_params.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/test/browser_test_utils.h"
@@ -29,6 +30,11 @@ class ChromeNavigationBrowserTest : public InProcessBrowserTest {
   ~ChromeNavigationBrowserTest() override {}
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
+    // Backgrounded renderer processes run at a lower priority, causing the
+    // tests to take more time to complete. Disable backgrounding so that the
+    // tests don't time out.
+    command_line->AppendSwitch(switches::kDisableRendererBackgrounding);
+
     ASSERT_TRUE(embedded_test_server()->Start());
   }