Enable SiteIsolationExtensions trial for developers.

chrome/browser/extensions/api/webstore_private/webstore_private_apitest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 92 matching lines @@
   ExtensionWebstorePrivateApiTest() {}
   ~ExtensionWebstorePrivateApiTest() override {}
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
     ExtensionApiTest::SetUpCommandLine(command_line);
     command_line->AppendSwitchASCII(
         switches::kAppsGalleryURL,
         "http://www.example.com/extensions/api_test");
   }
 
-  void SetUpInProcessBrowserTestFixture() override {
-    ExtensionApiTest::SetUpInProcessBrowserTestFixture();
+  void SetUpOnMainThread() override {
+    ExtensionApiTest::SetUpOnMainThread();
 
     // Start up the test server and get us ready for calling the install
     // API functions.
     host_resolver()->AddRule("www.example.com", "127.0.0.1");
     ASSERT_TRUE(StartEmbeddedTestServer());
     extensions::ExtensionInstallUI::set_disable_failure_ui_for_tests();
-  }
-
-  void SetUpOnMainThread() override {
-    ExtensionApiTest::SetUpOnMainThread();
 
     auto_confirm_install_.reset(
         new ScopedTestDialogAutoConfirm(ScopedTestDialogAutoConfirm::ACCEPT));
 
     ASSERT_TRUE(webstore_install_dir_.CreateUniqueTempDir());
     webstore_install_dir_copy_ = webstore_install_dir_.GetPath();
     WebstoreInstaller::SetDownloadDirectoryForTests(
         &webstore_install_dir_copy_);
   }
 
@@ skipping 300 matching lines @@
   content::GpuDataManager::GetInstance()->InitializeForTesting(
       json_blacklist, gpu_info);
   EXPECT_TRUE(content::GpuDataManager::GetInstance()->IsFeatureBlacklisted(
       gpu::GPU_FEATURE_TYPE_WEBGL));
 
   bool webgl_allowed = false;
   RunTest(webgl_allowed);
 }
 
 }  // namespace extensions