Implement ComplexFeature to support permission features with multiple rules.

chrome/common/extensions/features/manifest_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_MANIFEST_FEATURE_H_
 #define CHROME_COMMON_EXTENSIONS_FEATURES_MANIFEST_FEATURE_H_
 
-#include "chrome/common/extensions/features/feature.h"
+#include "chrome/common/extensions/features/simple_feature.h"
 
 namespace extensions {
 
-class ManifestFeature : public Feature {
+class ManifestFeature : public SimpleFeature {

[not at google - send to devlin, 2012/12/12 17:42:41]

now that Feature is an interface, can we make this compose with a Feature rather
than extending it?

[justinlin, 2012/12/14 12:26:26]

Hmm.. not sure how you mean by this? I thought about it a bit, but can't come up
with a way that this would make things nicer yet.

[not at google - send to devlin, 2012/12/14 19:10:42]

Something like this: https://codereview.chromium.org/11568034/

  public:
   ManifestFeature();
   virtual ~ManifestFeature();
 
   virtual Feature::Availability IsAvailableToContext(
       const Extension* extension,
       Feature::Context context,
       Feature::Platform platform) const OVERRIDE;
 };
 
 }  // extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_FEATURES_MANIFEST_FEATURE_H_