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

components/search_provider_logos/google_logo_api.cc

Index: components/search_provider_logos/google_logo_api.cc
diff --git a/components/search_provider_logos/google_logo_api.cc b/components/search_provider_logos/google_logo_api.cc
index 82772fd6c77aea3b914448e65ce88b3c27a51849..f0ab64f4c5e4077eac7be5f9a8ba9c652a234f10 100644
--- a/components/search_provider_logos/google_logo_api.cc
+++ b/components/search_provider_logos/google_logo_api.cc
@@ -11,6 +11,7 @@
 #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"
 
@@ -36,9 +37,12 @@ GURL GoogleAppendQueryparamsToLogoURL(const GURL& logo_url,
       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");