Replace string16 with base::string16.

chrome/browser/download/download_request_infobar_delegate.cc

Index: chrome/browser/download/download_request_infobar_delegate.cc
diff --git a/chrome/browser/download/download_request_infobar_delegate.cc b/chrome/browser/download/download_request_infobar_delegate.cc
index 6a91a5d7d476ee99cd66f17a76d797e1f3ca8e47..c61ea2c46db1ee7785d09f09a5a21e89a247b869 100644
--- a/chrome/browser/download/download_request_infobar_delegate.cc
+++ b/chrome/browser/download/download_request_infobar_delegate.cc
@@ -58,11 +58,11 @@ int DownloadRequestInfoBarDelegate::GetIconID() const {
   return IDR_INFOBAR_MULTIPLE_DOWNLOADS;
 }
 
-string16 DownloadRequestInfoBarDelegate::GetMessageText() const {
+base::string16 DownloadRequestInfoBarDelegate::GetMessageText() const {
   return l10n_util::GetStringUTF16(IDS_MULTI_DOWNLOAD_WARNING);
 }
 
-string16 DownloadRequestInfoBarDelegate::GetButtonLabel(
+base::string16 DownloadRequestInfoBarDelegate::GetButtonLabel(
     InfoBarButton button) const {
   return l10n_util::GetStringUTF16((button == BUTTON_OK) ?
       IDS_MULTI_DOWNLOAD_WARNING_ALLOW : IDS_MULTI_DOWNLOAD_WARNING_DENY);