Hardcode extensions::util::IsNewBookmarkAppsEnabled() to true, except on Mac.

chrome/browser/apps/app_shim/app_shim_interactive_uitest_mac.mm

Index: chrome/browser/apps/app_shim/app_shim_interactive_uitest_mac.mm
diff --git a/chrome/browser/apps/app_shim/app_shim_interactive_uitest_mac.mm b/chrome/browser/apps/app_shim/app_shim_interactive_uitest_mac.mm
index 951fda233651269df8628e931b3e12af1da2d766..6575b6d60aa3113fc2191a8556d02b0d627d7200 100644
--- a/chrome/browser/apps/app_shim/app_shim_interactive_uitest_mac.mm
+++ b/chrome/browser/apps/app_shim/app_shim_interactive_uitest_mac.mm
@@ -16,6 +16,7 @@
 #include "base/path_service.h"
 #include "base/process/launch.h"
 #include "base/strings/sys_string_conversions.h"
+#include "base/test/scoped_feature_list.h"
 #include "base/test/test_timeouts.h"
 #include "build/build_config.h"
 #include "chrome/browser/apps/app_browsertest_util.h"
@@ -28,8 +29,8 @@
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/web_applications/web_app_mac.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_paths.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/mac/app_mode_common.h"
 #include "content/public/test/test_utils.h"
 #include "extensions/browser/app_window/native_app_window.h"
@@ -49,22 +50,24 @@ class AppShimInteractiveTest : public extensions::PlatformAppBrowserTest {
   AppShimInteractiveTest()
       : auto_reset_(&g_app_shims_allow_update_and_launch_in_tests, true) {}
 
+  // testing::Test:
+  void SetUp() override {
+    PlatformAppBrowserTest::SetUp();
+    scoped_feature_list_.InitAndEnableFeature(features::kBookmarkApps);
+  }
+
   // Install a test app of |type| and reliably wait for its app shim to be
   // created on disk. Sets |shim_path_|.
   const extensions::Extension* InstallAppWithShim(AppType type,
                                                   const char* name);
 
-  void SetUpCommandLine(base::CommandLine* command_line) override {
-    PlatformAppBrowserTest::SetUpCommandLine(command_line);
-    command_line->AppendSwitch(switches::kEnableNewBookmarkApps);
-  }
-
  protected:
   base::FilePath shim_path_;
 
  private:
   // Temporarily enable app shims.
   base::AutoReset<bool> auto_reset_;
+  base::test::ScopedFeatureList scoped_feature_list_;
 
   DISALLOW_COPY_AND_ASSIGN(AppShimInteractiveTest);
 };