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

chrome/browser/ui/cocoa/autofill/autofill_notification_container_unittest.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/autofill/autofill_notification_container.h"
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/ui/autofill/autofill_dialog_types.h"
 #include "chrome/browser/ui/autofill/mock_autofill_dialog_view_delegate.h"
@@ skipping 22 matching lines @@
 
 TEST_F(AutofillNotificationContainerTest, Subviews) {
   // No subviews if there are no notifications.
   EXPECT_EQ(0U, [[[container_ view] subviews] count]);
 
   // Single notification adds one subview.
   std::vector<autofill::DialogNotification> notifications;
   notifications.push_back(
       autofill::DialogNotification(
           autofill::DialogNotification::REQUIRED_ACTION,
-          ASCIIToUTF16("test")));
+          base::ASCIIToUTF16("test")));
   ASSERT_FALSE(notifications[0].HasArrow());
   [container_ setNotifications:notifications];
 
   EXPECT_EQ(1U, [[[container_ view] subviews] count]);
 
   // 2 notifications, one with arrow - 2 views.
   notifications.push_back(
       autofill::DialogNotification(
           autofill::DialogNotification::REQUIRED_ACTION,
-          ASCIIToUTF16("test")));
+          base::ASCIIToUTF16("test")));
   ASSERT_FALSE(notifications[1].HasArrow());
   [container_ setNotifications:notifications];
 
   EXPECT_EQ(2U, [[[container_ view] subviews] count]);
 
   // Just to exercise code path.
   [container_ performLayout];
 }