[Extensions] Move Feature channel code into //extensions

extensions/common/features/feature.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 "extensions/common/features/feature.h"
 
 #include <map>
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
@@ skipping 28 matching lines @@
                                extension->manifest_version());
 }
 
 Feature::Availability Feature::IsAvailableToEnvironment() const {
   return IsAvailableToManifest("",  // extension_id
                                Manifest::TYPE_UNKNOWN,
                                Manifest::INVALID_LOCATION,
                                -1);  // manifest_version
 }
 
-Feature::Feature() : no_parent_(false) {}
+Feature::Feature() : no_parent_(false), check_channel_(false) {}
 
 Feature::~Feature() {}
 
 }  // namespace extensions