Implement ComplexFeature to support permission features with multiple rules.

chrome/common/extensions/features/manifest_feature.h

Index: chrome/common/extensions/features/manifest_feature.h
diff --git a/chrome/common/extensions/features/manifest_feature.h b/chrome/common/extensions/features/manifest_feature.h
index 0ec0cd72b742f698351bc6d799ba53701cc3949e..4d239694ee50ce24296e3cf3fc3bd2aeb8fed07a 100644
--- a/chrome/common/extensions/features/manifest_feature.h
+++ b/chrome/common/extensions/features/manifest_feature.h
@@ -5,11 +5,11 @@
 #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 {
  public:
   ManifestFeature();
   virtual ~ManifestFeature();