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

chrome/browser/ui/cocoa/media_picker/desktop_media_picker_controller_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/media_picker/desktop_media_picker_controller.h"
 
 #include "base/bind.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/run_loop.h"
 #include "chrome/browser/media/desktop_media_list_observer.h"
@@ skipping 39 matching lines @@
 
     DesktopMediaPicker::DoneCallback callback =
         base::Bind(&DesktopMediaPickerControllerTest::OnResult,
                    base::Unretained(this));
 
     controller_.reset(
         [[DesktopMediaPickerController alloc]
             initWithMediaList:scoped_ptr<DesktopMediaList>(media_list_)
                        parent:nil
                      callback:callback
-                      appName:ASCIIToUTF16("Screenshare Test")]);
+                      appName:base::ASCIIToUTF16("Screenshare Test")]);
   }
 
   virtual void TearDown() OVERRIDE {
     controller_.reset();
     CocoaTest::TearDown();
   }
 
   bool WaitForCallback() {
     if (!callback_called_) {
       base::RunLoop().RunUntilIdle();
@@ skipping 108 matching lines @@
   media_list_->SetSourceThumbnail(0);
   EXPECT_NE(version, [[items objectAtIndex:0] imageVersion]);
 }
 
 TEST_F(DesktopMediaPickerControllerTest, RemoveSource) {
   [controller_ showWindow:nil];
 
   media_list_->AddSource(0);
   media_list_->AddSource(1);
   media_list_->AddSource(2);
-  media_list_->SetSourceName(1, ASCIIToUTF16("foo"));
+  media_list_->SetSourceName(1, base::ASCIIToUTF16("foo"));
 
   NSArray* items = [controller_ items];
   EXPECT_EQ(3U, [items count]);
   EXPECT_NSEQ(@"foo", [[items objectAtIndex:1] imageTitle]);
 }