Implement API features for the Extension API feature system

chrome/common/extensions/features/simple_feature.cc

 // 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.
 
 #include "chrome/common/extensions/features/simple_feature.h"
 
 #include <map>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 190 matching lines @@
       extension_types_ == other.extension_types_ &&
       contexts_ == other.contexts_ &&
       matches_ == other.matches_ &&
       location_ == other.location_ &&
       platform_ == other.platform_ &&
       min_manifest_version_ == other.min_manifest_version_ &&
       max_manifest_version_ == other.max_manifest_version_ &&
       channel_ == other.channel_;
 }
 
-void SimpleFeature::Parse(const DictionaryValue* value) {
+std::string SimpleFeature::Parse(const DictionaryValue* value) {
   ParseURLPatterns(value, "matches", &matches_);
   ParseSet(value, "whitelist", &whitelist_);
+  ParseSet(value, "dependencies", &dependencies_);
   ParseEnumSet<Manifest::Type>(value, "extension_types", &extension_types_,
                                 g_mappings.Get().extension_types);
   ParseEnumSet<Context>(value, "contexts", &contexts_,
                         g_mappings.Get().contexts);
   ParseEnum<Location>(value, "location", &location_,
                       g_mappings.Get().locations);
   ParseEnum<Platform>(value, "platform", &platform_,
                       g_mappings.Get().platforms);
   value->GetInteger("min_manifest_version", &min_manifest_version_);
   value->GetInteger("max_manifest_version", &max_manifest_version_);
   ParseEnum<VersionInfo::Channel>(
       value, "channel", &channel_,
       g_mappings.Get().channels);
+  if (matches_.is_empty() && contexts_.count(WEB_PAGE_CONTEXT) != 0) {
+    return name() + ": Allowing web_page contexts requires supplying a value " +
+        "for matches.";
+  }
+  return "";
 }
 
 Feature::Availability SimpleFeature::IsAvailableToManifest(
     const std::string& extension_id,
     Manifest::Type type,
     Location location,
     int manifest_version,
     Platform platform) const {
   // Component extensions can access any feature.
   if (location == COMPONENT_LOCATION)
@@ skipping 189 matching lines @@
   DCHECK(id_hash.length() == base::kSHA1Length);
   const std::string hexencoded_id_hash = base::HexEncode(id_hash.c_str(),
       id_hash.length());
   if (whitelist_.find(hexencoded_id_hash) != whitelist_.end())
     return true;
 
   return false;
 }
 
 }  // namespace extensions