Revert of Move JoinString to the base namespace

android_webview/native/aw_web_contents_delegate.cc

Index: android_webview/native/aw_web_contents_delegate.cc
diff --git a/android_webview/native/aw_web_contents_delegate.cc b/android_webview/native/aw_web_contents_delegate.cc
index 1d22633c80a58b4502084ca41ece50e77d5cc780..bc7e0264db69e34e5733b9d127e8193946ab63bc 100644
--- a/android_webview/native/aw_web_contents_delegate.cc
+++ b/android_webview/native/aw_web_contents_delegate.cc
@@ -16,7 +16,6 @@
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_util.h"
-#include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
@@ -115,7 +114,7 @@
       web_contents->GetRenderViewHost()->GetRoutingID(),
       mode_flags,
       ConvertUTF16ToJavaString(env,
-          base::JoinString(params.accept_types, base::ASCIIToUTF16(","))).obj(),
+        JoinString(params.accept_types, ',')).obj(),
       params.title.empty() ? NULL :
           ConvertUTF16ToJavaString(env, params.title).obj(),
       params.default_file_name.empty() ? NULL :
@@ -294,7 +293,7 @@
     mode = FileChooserParams::Open;
   }
   DVLOG(0) << "File Chooser result: mode = " << mode
-           << ", file paths = " << base::JoinString(file_path_str, ":");
+           << ", file paths = " << JoinString(file_path_str, ":");
   rvh->FilesSelectedInChooser(files, mode);
 }