When allowing an extension file:/// URL access, grant its process access to that scheme.

chrome/browser/extensions/extension_apitest.cc

 // Copyright (c) 2011 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 "chrome/browser/extensions/extension_apitest.h"
 
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_test_api.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_service.h"
 
 namespace {
 
 const char kTestServerPort[] = "testServer.port";
+const char kTestDataDirectory[] = "testDataDirectory";
 
 };  // namespace
 
 ExtensionApiTest::ExtensionApiTest() {}
 
 ExtensionApiTest::~ExtensionApiTest() {}
 
 ExtensionApiTest::ResultCatcher::ResultCatcher()
     : profile_restriction_(NULL),
       waiting_(false) {
@@ skipping 55 matching lines @@
       break;
 
     default:
       NOTREACHED();
   }
 }
 
 void ExtensionApiTest::SetUpInProcessBrowserTestFixture() {
   DCHECK(!test_config_.get()) << "Previous test did not clear config state.";
   test_config_.reset(new DictionaryValue());
+  test_config_->SetString(kTestDataDirectory,
+                          net::FilePathToFileURL(test_data_dir_).spec());
   ExtensionTestGetConfigFunction::set_test_config_state(test_config_.get());
 }
 
 void ExtensionApiTest::TearDownInProcessBrowserTestFixture() {
   ExtensionTestGetConfigFunction::set_test_config_state(NULL);
   test_config_.reset(NULL);
 }
 
 bool ExtensionApiTest::RunExtensionTest(const char* extension_name) {
   return RunExtensionTestImpl(extension_name, "", false, true, false);
@@ skipping 120 matching lines @@
     return NULL;
   }
   return extension;
 }
 
 bool ExtensionApiTest::StartTestServer() {
   if (!test_server()->Start())
     return false;
 
   // Build a dictionary of values that tests can use to build URLs that
-  // access the test server.  Tests can see these values using the extension
-  // API function chrome.test.getConfig().
+  // access the test server and local file system.  Tests can see these values
+  // using the extension API function chrome.test.getConfig().
   test_config_->SetInteger(kTestServerPort,
                            test_server()->host_port_pair().port());
 
   return true;
 }
 
 void ExtensionApiTest::SetUpCommandLine(CommandLine* command_line) {
   ExtensionBrowserTest::SetUpCommandLine(command_line);
   test_data_dir_ = test_data_dir_.AppendASCII("api_test");
 }