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

chrome/test/chromedriver/keycode_text_conversion_unittest.cc

Index: chrome/test/chromedriver/keycode_text_conversion_unittest.cc
diff --git a/chrome/test/chromedriver/keycode_text_conversion_unittest.cc b/chrome/test/chromedriver/keycode_text_conversion_unittest.cc
index 5c95fa0fb380f35875178917a1b50cd99b016979..fc2a82b816cb802065ff78d64b9cfc6c37dbe5d0 100644
--- a/chrome/test/chromedriver/keycode_text_conversion_unittest.cc
+++ b/chrome/test/chromedriver/keycode_text_conversion_unittest.cc
@@ -14,7 +14,7 @@
 
 namespace {
 
-void CheckCharToKeyCode16(char16 character, ui::KeyboardCode key_code,
+void CheckCharToKeyCode16(base::char16 character, ui::KeyboardCode key_code,
                           int modifiers) {
   ui::KeyboardCode actual_key_code = ui::VKEY_UNKNOWN;
   int actual_modifiers = 0;
@@ -42,7 +42,7 @@ void CheckCharToKeyCode(wchar_t character, ui::KeyboardCode key_code,
 void CheckCantConvertChar(wchar_t character) {
   std::wstring character_string;
   character_string.push_back(character);
-  char16 character_utf16 = base::WideToUTF16(character_string)[0];
+  base::char16 character_utf16 = base::WideToUTF16(character_string)[0];
   ui::KeyboardCode actual_key_code = ui::VKEY_UNKNOWN;
   int actual_modifiers = 0;
   std::string error_msg;