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

chrome/browser/ui/cocoa/tabs/tab_controller_unittest.mm

 // Copyright (c) 2011 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>
 
 #import "base/mac/scoped_nsobject.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/ui/cocoa/cocoa_test_helper.h"
 #import "chrome/browser/ui/cocoa/tabs/media_indicator_view.h"
@@ skipping 57 matching lines @@
 - (void)commandDispatch:(TabStripModel::ContextMenuCommand)command
           forController:(TabController*)controller {
 }
 - (BOOL)isCommandEnabled:(TabStripModel::ContextMenuCommand)command
            forController:(TabController*)controller {
   return NO;
 }
 - (ui::SimpleMenuModel*)contextMenuModelForController:(TabController*)controller
     menuDelegate:(ui::SimpleMenuModel::Delegate*)delegate {
   ui::SimpleMenuModel* model = new ui::SimpleMenuModel(delegate);
-  model->AddItem(1, ASCIIToUTF16("Hello World"));
-  model->AddItem(2, ASCIIToUTF16("Allays"));
-  model->AddItem(3, ASCIIToUTF16("Chromium"));
+  model->AddItem(1, base::ASCIIToUTF16("Hello World"));
+  model->AddItem(2, base::ASCIIToUTF16("Allays"));
+  model->AddItem(3, base::ASCIIToUTF16("Chromium"));
   return model;
 }
 - (id<TabDraggingEventTarget>)dragController {
   return dragController_.get();
 }
 @end
 
 namespace {
 
 CGFloat LeftMargin(NSRect superFrame, NSRect subFrame) {
@@ skipping 451 matching lines @@
           [[controller view] setFrame:tabFrame];
           CheckForExpectedLayoutAndVisibilityOfSubviews(controller);
           --tabFrame.size.width;
         }
       }
     }
   }
 }
 
 }  // namespace