Rewrite std::string("") to std::string(), Linux edition.

chrome/common/extensions/manifest_tests/extension_manifests_platformapp_unittest.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 "base/command_line.h"
 #include "base/json/json_file_value_serializer.h"
 #include "base/memory/linked_ptr.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/background_info.h"
 #include "chrome/common/extensions/csp_handler.h"
@@ skipping 80 matching lines @@
   std::string test_id = "ahplfneplbnjcflhdgkkjeiglkkfeelb";
   CommandLine::ForCurrentProcess()->AppendSwitchASCII(
       switches::kWhitelistedExtensionID, test_id);
   scoped_refptr<Extension> extension =
       LoadAndExpectSuccess("init_platform_app_csp.json");
   EXPECT_EQ(0U, extension->install_warnings().size())
       << "Unexpected warning " << extension->install_warnings()[0].message;
   EXPECT_TRUE(extension->is_platform_app());
   EXPECT_EQ(
       "default-src 'self' https://www.google.com",
-      CSPInfo::GetResourceContentSecurityPolicy(extension, ""));
+      CSPInfo::GetResourceContentSecurityPolicy(extension, std::string()));
 
   // But even whitelisted ones must specify a secure policy.
   LoadAndExpectError(
       "init_platform_app_csp_insecure.json",
       errors::kInsecureContentSecurityPolicy);
 }
 
 TEST_F(PlatformAppsManifestTest, CertainApisRequirePlatformApps) {
   // Put APIs here that should be restricted to platform apps, but that haven't
   // yet graduated from experimental.
@@ skipping 32 matching lines @@
 
   // Now try again with the experimental flag set.
   CommandLine::ForCurrentProcess()->AppendSwitch(
       switches::kEnableExperimentalExtensionApis);
   for (size_t i = 0; i < arraysize(kPlatformAppExperimentalApis); ++i) {
     LoadAndExpectSuccess(Manifest(manifests[i].get(), ""));
   }
 }
 
 }  // namespace extensions