Remove legacy StartsWithASCII function.

android_webview/native/aw_media_url_interceptor.cc

Index: android_webview/native/aw_media_url_interceptor.cc
diff --git a/android_webview/native/aw_media_url_interceptor.cc b/android_webview/native/aw_media_url_interceptor.cc
index 39e9b549e37546100d64f993f32fd109d4cc1224..fd85ffc5148d71feffc803df7b025a969c7641cd 100644
--- a/android_webview/native/aw_media_url_interceptor.cc
+++ b/android_webview/native/aw_media_url_interceptor.cc
@@ -20,7 +20,7 @@ bool AwMediaUrlInterceptor::Intercept(const std::string& url,
   asset_file_prefix.append(url::kStandardSchemeSeparator);
   asset_file_prefix.append(android_webview::kAndroidAssetPath);
 
-  if (base::StartsWithASCII(url, asset_file_prefix, true)) {
+  if (base::StartsWith(url, asset_file_prefix, base::CompareCase::SENSITIVE)) {
     std::string filename(url);
     base::ReplaceFirstSubstringAfterOffset(
         &filename, 0, asset_file_prefix, "assets/");