Use base::StartWith() in more places when appropriate.

media/base/key_systems.cc

 // Copyright 2013 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/base/key_systems.h"
 
 #include <stddef.h>
 
 #include <memory>
 
@@ skipping 151 matching lines @@
 
   // Chromecast defines behaviors for Cast clients within its reverse domain.
   const char kChromecastRoot[] = "com.chromecast";
   if (IsChildKeySystemOf(key_system, kChromecastRoot))
     return true;
 
   // Implementations that do not have a specification or appropriate glue code
   // can use the "x-" prefix to avoid conflicting with and advertising support
   // for real key system names. Use is discouraged.
   const char kExcludedPrefix[] = "x-";
-  if (key_system.find(kExcludedPrefix, 0, arraysize(kExcludedPrefix) - 1) == 0)
-    return true;
-
-  return false;
+  return base::StartsWith(key_system, kExcludedPrefix,
+                          base::CompareCase::SENSITIVE);
 }
 
 class KeySystemsImpl : public KeySystems {
  public:
   static KeySystemsImpl* GetInstance();
 
   void UpdateIfNeeded();
 
   std::string GetKeySystemNameForUMA(const std::string& key_system) const;
 
@@ skipping 543 matching lines @@
                                uint32_t mask) {
   KeySystemsImpl::GetInstance()->AddCodecMask(media_type, codec, mask);
 }
 
 MEDIA_EXPORT void AddMimeTypeCodecMask(const std::string& mime_type,
                                        uint32_t mask) {
   KeySystemsImpl::GetInstance()->AddMimeTypeCodecMask(mime_type, mask);
 }
 
 }  // namespace media