Move StartsWith[ASCII] to base namespace.

ios/chrome/app/safe_mode_util_unittest.cc

Index: ios/chrome/app/safe_mode_util_unittest.cc
diff --git a/ios/chrome/app/safe_mode_util_unittest.cc b/ios/chrome/app/safe_mode_util_unittest.cc
index 3164d59fc7e13ebb4b5589efbc20fac831b2ce37..1c9de677511e7cb5377f920320e93f1fee8a5b4d 100644
--- a/ios/chrome/app/safe_mode_util_unittest.cc
+++ b/ios/chrome/app/safe_mode_util_unittest.cc
@@ -27,7 +27,7 @@ TEST_F(SafeModeUtilTest, GetAllImages) {
   string lib_system_prefix("libSystem");
   for (size_t i = 0; i < images.size(); ++i) {
     string base_name = base::FilePath(images[i]).BaseName().value();
-    if (StartsWithASCII(base_name, lib_system_prefix, true)) {
+    if (base::StartsWithASCII(base_name, lib_system_prefix, true)) {
       found_lib_system = true;
       break;
     }