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

components/search_provider_logos/google_logo_api.cc

 // Copyright 2014 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 "components/search_provider_logos/google_logo_api.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 
 #include "base/base64.h"
 #include "base/json/json_reader.h"
 #include "base/memory/ref_counted_memory.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/values.h"
 
 namespace search_provider_logos {
 
 namespace {
 const char kResponsePreamble[] = ")]}'";
 }
 
 GURL GoogleAppendQueryparamsToLogoURL(const GURL& logo_url,
                                       const std::string& fingerprint,
                                       bool wants_cta,
                                       bool gray_background) {
   // Note: we can't just use net::AppendQueryParameter() because it escapes
   // ":" to "%3A", but the server requires the colon not to be escaped.
   // See: http://crbug.com/413845
 
   // TODO(newt): Switch to using net::AppendQueryParameter once it no longer
   // escapes ":"
   if (!fingerprint.empty() || wants_cta) {
     std::string query(logo_url.query());
     if (!query.empty())
       query += "&";
 
     query += "async=";
-    std::vector<std::string> params;
-    if (!fingerprint.empty())
-      params.push_back("es_dfp:" + fingerprint);
+    std::vector<base::StringPiece> params;
+    std::string fingerprint_param;
+    if (!fingerprint.empty()) {
+      fingerprint_param = "es_dfp:" + fingerprint;
+      params.push_back(fingerprint_param);
+    }
 
     if (wants_cta)
       params.push_back("cta:1");
 
     if (gray_background) {
       params.push_back("transp:1");
       params.push_back("graybg:1");
     }
 
     query += base::JoinString(params, ",");
@@ skipping 91 matching lines @@
     logo->metadata.can_show_after_expiration = true;
   }
   logo->metadata.expiration_time = response_time + time_to_live;
 
   // If this point is reached, parsing has succeeded.
   *parsing_failed = false;
   return logo;
 }
 
 }  // namespace search_provider_logos