Change uses of base::JoinString to pass StringPieces where possible.

chrome/browser/extensions/chrome_content_verifier_delegate.cc

 // Copyright 2015 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/chrome_content_verifier_delegate.h"
 
 #include <algorithm>
 #include <memory>
 #include <set>
 #include <vector>
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/syslog_logging.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/version.h"
 #include "build/build_config.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_registry.h"
@@ skipping 140 matching lines @@
 ContentVerifierKey ChromeContentVerifierDelegate::GetPublicKey() {
   return ContentVerifierKey(kWebstoreSignaturesPublicKey,
                             kWebstoreSignaturesPublicKeySize);
 }
 
 GURL ChromeContentVerifierDelegate::GetSignatureFetchUrl(
     const std::string& extension_id,
     const base::Version& version) {
   // TODO(asargent) Factor out common code from the extension updater's
   // ManifestFetchData class that can be shared for use here.
-  std::vector<std::string> parts;
-  parts.push_back("uc");
-  parts.push_back("installsource=signature");
-  parts.push_back("id=" + extension_id);
-  parts.push_back("v=" + version.GetString());
-  std::string x_value =
-      net::EscapeQueryParamValue(base::JoinString(parts, "&"), true);
+  std::string id_part = "id=" + extension_id;
+  std::string version_part = "v=" + version.GetString();
+  std::string x_value = net::EscapeQueryParamValue(
+      base::JoinString({"uc", "installsource=signature", id_part, version_part},
+                       "&"),
+      true);
   std::string query = "response=redirect&x=" + x_value;
 
   GURL base_url = extension_urls::GetWebstoreUpdateUrl();
   GURL::Replacements replacements;
   replacements.SetQuery(query.c_str(), url::Component(0, query.length()));
   return base_url.ReplaceComponents(replacements);
 }
 
 std::set<base::FilePath> ChromeContentVerifierDelegate::GetBrowserImagePaths(
     const extensions::Extension* extension) {
@@ skipping 62 matching lines @@
   }
 }
 
 // static
 void ChromeContentVerifierDelegate::set_policy_reinstall_action_for_test(
     base::Callback<void(base::TimeDelta delay)>* action) {
   g_reinstall_action_for_test = action;
 }
 
 }  // namespace extensions