Only set the channel from ExtensionSystem if there hasn't been one set already.

chrome/common/extensions/features/feature.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_COMMON_EXTENSIONS_FEATURES_FEATURE_H_
 #define CHROME_COMMON_EXTENSIONS_FEATURES_FEATURE_H_
 
 #include <set>
 #include <string>
 
@@ skipping 51 matching lines @@
     INVALID_MAX_MANIFEST_VERSION,
     NOT_PRESENT,
     UNSUPPORTED_CHANNEL,
   };
 
   Feature();
   Feature(const Feature& other);
   virtual ~Feature();
 
   // Gets the current channel as seen by the Feature system.
-  // Defaults to CHANNEL_STABLE.
   static chrome::VersionInfo::Channel GetCurrentChannel();
 
   // Sets the current channel as seen by the Feature system. In the browser
   // process this should be chrome::VersionInfo::GetChannel(), and in the
   // renderer this will need to come from an IPC.
   static void SetCurrentChannel(chrome::VersionInfo::Channel channel);
 
+  // Gets the default channel as seen by the Feature system.
+  static chrome::VersionInfo::Channel GetDefaultChannel();
+
   // Scoped channel setter. Use for tests.
   class ScopedCurrentChannel {
    public:
     explicit ScopedCurrentChannel(chrome::VersionInfo::Channel channel)
         : original_channel_(chrome::VersionInfo::CHANNEL_UNKNOWN) {
       original_channel_ = GetCurrentChannel();
       SetCurrentChannel(channel);
     }
 
     ~ScopedCurrentChannel() {
@@ skipping 82 matching lines @@
   Location location_;  // we only care about component/not-component now
   Platform platform_;  // we only care about chromeos/not-chromeos now
   int min_manifest_version_;
   int max_manifest_version_;
   chrome::VersionInfo::Channel channel_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_FEATURES_FEATURE_H_