Update some uses of char16 to use the base:: namespace.

chrome/test/chromedriver/keycode_text_conversion_x.cc

 // 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.
 
 #include "chrome/test/chromedriver/keycode_text_conversion.h"
 
 #include <algorithm>
 #include <X11/keysym.h>
 #include <X11/XKBlib.h>
 #include <X11/Xlib.h>
@@ skipping 211 matching lines @@
   uint16 character = ui::GetCharacterFromXEvent(&event);
 
   if (!character)
     *text = std::string();
   else
     *text = base::UTF16ToUTF8(base::string16(1, character));
   return true;
 }
 
 bool ConvertCharToKeyCode(
-    char16 key,
+    base::char16 key,
     ui::KeyboardCode* key_code,
     int* necessary_modifiers,
     std::string* error_msg) {
   std::string key_string(base::UTF16ToUTF8(base::string16(1, key)));
   bool found = false;
   ui::KeyboardCode test_code;
   int test_modifiers;
   *error_msg = std::string();
   std::string conv_string;
   for (size_t i = 0; i < arraysize(kKeyCodeToXKeyCode); ++i) {
@@ skipping 17 matching lines @@
       found = true;
       break;
     }
   }
   if (found) {
     *key_code = test_code;
     *necessary_modifiers = test_modifiers;
   }
   return found;
 }