Skip base::string16 if not necessary for WebString <-> ASCII conversion

media/blink/webencryptedmediaclient_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/blink/webencryptedmediaclient_impl.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
@@ skipping 149 matching lines @@
     blink::WebEncryptedMediaRequest request,
     const blink::WebString& error_message) {
   request.requestNotSupported(error_message);
 }
 
 WebEncryptedMediaClientImpl::Reporter* WebEncryptedMediaClientImpl::GetReporter(
     const blink::WebString& key_system) {
   // Assumes that empty will not be found by GetKeySystemNameForUMA().
   // TODO(sandersd): Avoid doing ASCII conversion more than once.
   std::string key_system_ascii;
-  if (base::IsStringASCII(key_system))
-    key_system_ascii = base::UTF16ToASCII(base::StringPiece16(key_system));
+  if (key_system.containsOnlyASCII())
+    key_system_ascii = key_system.ascii();
 
   // Return a per-frame singleton so that UMA reports will be once-per-frame.
   std::string uma_name = GetKeySystemNameForUMA(key_system_ascii);
   Reporter* reporter = reporters_.get(uma_name);
   if (!reporter) {
     reporter = new Reporter(uma_name);
     reporters_.add(uma_name, base::WrapUnique(reporter));
   }
   return reporter;
 }
 
 }  // namespace media