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

chrome/browser/ui/cocoa/validation_message_bubble_controller_unittest.mm

 // Copyright (c) 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 <Cocoa/Cocoa.h>
 
 #include "base/strings/utf_string_conversions.h"
 #import "chrome/browser/ui/cocoa/validation_message_bubble_controller.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 static NSView* constructView(const char* main_text, const char* sub_text) {
   return [ValidationMessageBubbleController
-      constructContentView:UTF8ToUTF16(main_text)
-                   subText:UTF8ToUTF16(sub_text)];
+      constructContentView:base::UTF8ToUTF16(main_text)
+                   subText:base::UTF8ToUTF16(sub_text)];
 }
 
 TEST(ValidationMessageBubbleControllerTest, FrameSize) {
   NSRect shortMainNoSubFrame = [constructView("abc", "") frame];
   EXPECT_GE(NSWidth(shortMainNoSubFrame), 40);
   EXPECT_GT(NSHeight(shortMainNoSubFrame), 0);
 
   NSRect longMainNoSubFrame = [constructView(
       "very very very long text which overlfows the maximum window width. "
       "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod"
       " tempor incididunt ut labore et dolore magna aliqua.", "") frame];
   EXPECT_LT(NSWidth(longMainNoSubFrame), 500);
   EXPECT_LT(NSHeight(shortMainNoSubFrame), NSHeight(longMainNoSubFrame));
 
   NSRect shortMainMediumSubFrame = [constructView("abc", "foo bar baz") frame];
   EXPECT_GT(NSWidth(shortMainMediumSubFrame), NSWidth(shortMainNoSubFrame));
   EXPECT_GT(NSHeight(shortMainMediumSubFrame), NSHeight(shortMainNoSubFrame));
 
   NSRect shortMainLongSubFrame =  [constructView("abc",
       "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod"
       " tempor incididunt ut labore et dolore magna aliqua.") frame];
   EXPECT_GT(NSWidth(shortMainLongSubFrame), NSWidth(shortMainMediumSubFrame));
   EXPECT_LT(NSWidth(shortMainLongSubFrame), 500);
   EXPECT_GT(NSHeight(shortMainLongSubFrame), NSHeight(shortMainMediumSubFrame));
 }
 
 }