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

chrome/browser/ui/cocoa/profile_signin_confirmation_view_controller.mm

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/profile_signin_confirmation_view_controller.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/callback_helpers.h"
@@ skipping 234 matching lines @@
   [promptBox_ setFillColor:gfx::SkColorToCalibratedNSColor(
       ui::GetSigninConfirmationPromptBarColor(
           ui::kSigninConfirmationPromptBarBackgroundAlpha))];
   [promptBox_ setBoxType:NSBoxCustom];
   [promptBox_ setTitlePosition:NSNoTitle];
   [[self view] addSubview:promptBox_];
 
   // Prompt text.
   size_t offset;
   const base::string16 domain =
-      ASCIIToUTF16(gaia::ExtractDomainName(username_));
-  const base::string16 username = ASCIIToUTF16(username_);
+      base::ASCIIToUTF16(gaia::ExtractDomainName(username_));
+  const base::string16 username = base::ASCIIToUTF16(username_);
   const base::string16 prompt_text =
       l10n_util::GetStringFUTF16(
           IDS_ENTERPRISE_SIGNIN_ALERT_NEW_STYLE,
           domain, &offset);
   promptField_.reset(
       [AddTextField(promptBox_, prompt_text, chrome_style::kTextFontStyle)
           retain]);
   MakeTextBold(promptField_, offset, domain.size());
   [promptField_ setFrame:ComputeFrame(
         [promptField_ attributedStringValue], width, 0.0)];
@@ skipping 170 matching lines @@
 
 - (NSButton*)createProfileButton {
   return createProfileButton_.get();
 }
 
 - (NSTextView*)explanationField {
   return explanationField_.get();
 }
 
 @end