Remove legacy StartsWithASCII function.

content/public/test/browser_test_utils.cc

Index: content/public/test/browser_test_utils.cc
diff --git a/content/public/test/browser_test_utils.cc b/content/public/test/browser_test_utils.cc
index bbae7f8c2f7792c1078ec47374371a29b09e8b22..f1542de698d87819e522b27c1a65bded1959b08a 100644
--- a/content/public/test/browser_test_utils.cc
+++ b/content/public/test/browser_test_utils.cc
@@ -234,7 +234,8 @@ scoped_ptr<net::test_server::HttpResponse> CrossSiteRedirectResponseHandler(
     const GURL& server_base_url,
     const net::test_server::HttpRequest& request) {
   std::string prefix("/cross-site/");
-  if (!base::StartsWithASCII(request.relative_url, prefix, true))
+  if (!base::StartsWith(request.relative_url, prefix,
+                        base::CompareCase::SENSITIVE))
     return scoped_ptr<net::test_server::HttpResponse>();
 
   std::string params = request.relative_url.substr(prefix.length());