Revert of Move JoinString to the base namespace

content/browser/speech/google_streaming_remote_engine.cc

Index: content/browser/speech/google_streaming_remote_engine.cc
diff --git a/content/browser/speech/google_streaming_remote_engine.cc b/content/browser/speech/google_streaming_remote_engine.cc
index 0082cec67d9eea74181a7958f89b57395bb3b20c..fc8c6d242548b4d03b9215826b8d279f57843ec8 100644
--- a/content/browser/speech/google_streaming_remote_engine.cc
+++ b/content/browser/speech/google_streaming_remote_engine.cc
@@ -320,7 +320,7 @@
   downstream_args.push_back("output=pb");
   GURL downstream_url(std::string(kWebServiceBaseUrl) +
                       std::string(kDownstreamUrl) +
-                      base::JoinString(downstream_args, "&"));
+                      JoinString(downstream_args, '&'));
 
   downstream_fetcher_ = URLFetcher::Create(
       kDownstreamUrlFetcherIdForTesting, downstream_url, URLFetcher::GET, this);
@@ -372,7 +372,7 @@
   }
   GURL upstream_url(std::string(kWebServiceBaseUrl) +
                     std::string(kUpstreamUrl) +
-                    base::JoinString(upstream_args, "&"));
+                    JoinString(upstream_args, '&'));
 
   upstream_fetcher_ = URLFetcher::Create(kUpstreamUrlFetcherIdForTesting,
                                          upstream_url, URLFetcher::POST, this);