Update some uses of UTF conversions in chrome/browser to use the base:: namespace.

chrome/browser/ui/cocoa/infobars/mock_confirm_infobar_delegate.cc

Index: chrome/browser/ui/cocoa/infobars/mock_confirm_infobar_delegate.cc
diff --git a/chrome/browser/ui/cocoa/infobars/mock_confirm_infobar_delegate.cc b/chrome/browser/ui/cocoa/infobars/mock_confirm_infobar_delegate.cc
index 211078382df78b9045dc18b42956b61458940450..65ff19672c0f6abd9cd636eeaaa16f95903fb606 100644
--- a/chrome/browser/ui/cocoa/infobars/mock_confirm_infobar_delegate.cc
+++ b/chrome/browser/ui/cocoa/infobars/mock_confirm_infobar_delegate.cc
@@ -32,12 +32,12 @@ int MockConfirmInfoBarDelegate::GetIconID() const {
 
 base::string16 MockConfirmInfoBarDelegate::GetMessageText() const {
   message_text_accessed_ = true;
-  return ASCIIToUTF16(kMessage);
+  return base::ASCIIToUTF16(kMessage);
 }
 
 base::string16 MockConfirmInfoBarDelegate::GetButtonLabel(
     InfoBarButton button) const {
-  return ASCIIToUTF16((button == BUTTON_OK) ? "OK" : "Cancel");
+  return base::ASCIIToUTF16((button == BUTTON_OK) ? "OK" : "Cancel");
 }
 
 bool MockConfirmInfoBarDelegate::Accept() {