Extension-created windows should share the creator's BrowingInstance.

chrome/browser/extensions/extension_apitest.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_APITEST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_APITEST_H_
 
 #include <deque>
 #include <string>
 
@@ skipping 54 matching lines @@
 
  protected:
   // InProcessBrowserTest:
   void SetUpInProcessBrowserTestFixture() override;
   void TearDownInProcessBrowserTestFixture() override;
 
   // Load |extension_name| and wait for pass / fail notification.
   // |extension_name| is a directory in "test/data/extensions/api_test".
   bool RunExtensionTest(const std::string& extension_name);
 
+  // Similar to RunExtensionTest, except sets an additional string argument
+  // |customArg| to the test config object.
+  bool RunExtensionTestWithArg(const std::string& extension_name,
+                               const char* custom_arg);
+
   // Same as RunExtensionTest, but enables the extension for incognito mode.
   bool RunExtensionTestIncognito(const std::string& extension_name);
 
   // Same as RunExtensionTest, but ignores any warnings in the manifest.
   bool RunExtensionTestIgnoreManifestWarnings(
       const std::string& extension_name);
 
   // Same as RunExtensionTest, allow old manifest ersions.
   bool RunExtensionTestAllowOldManifestVersion(
       const std::string& extension_name);
@@ skipping 84 matching lines @@
   scoped_ptr<base::DictionaryValue> test_config_;
 
   // Hold the test WebSocket server.
   scoped_ptr<net::SpawnedTestServer> websocket_server_;
 
   // Hold the test FTP server.
   scoped_ptr<net::SpawnedTestServer> ftp_server_;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_APITEST_H_