Add utf_string_conversions to base namespace.

chrome/test/chromedriver/key_converter_unittest.cc

Index: chrome/test/chromedriver/key_converter_unittest.cc
diff --git a/chrome/test/chromedriver/key_converter_unittest.cc b/chrome/test/chromedriver/key_converter_unittest.cc
index fbf63d76f8ecaa568b654c30570ea4cc186d7215..48f801b629c79543571944ec0a178614dbd7020d 100644
--- a/chrome/test/chromedriver/key_converter_unittest.cc
+++ b/chrome/test/chromedriver/key_converter_unittest.cc
@@ -152,9 +152,10 @@ TEST(KeyConverter, WebDriverSpecialNonCharKey) {
 TEST(KeyConverter, FrenchKeyOnEnglishLayout) {
   KeyEvent event_array[] = {
       CreateKeyDownEvent(ui::VKEY_UNKNOWN, 0),
-      CreateCharEvent(WideToUTF8(L"\u00E9"), WideToUTF8(L"\u00E9"), 0),
+      CreateCharEvent(base::WideToUTF8(L"\u00E9"),
+                      base::WideToUTF8(L"\u00E9"), 0),
       CreateKeyUpEvent(ui::VKEY_UNKNOWN, 0)};
-  CheckEventsReleaseModifiers(WideToUTF16(L"\u00E9"),
+  CheckEventsReleaseModifiers(base::WideToUTF16(L"\u00E9"),
       event_array, arraysize(event_array));
 }