Load extensions features file separately when needed

chrome/common/extensions/features/base_feature_provider.h

Index: chrome/common/extensions/features/base_feature_provider.h
diff --git a/chrome/common/extensions/features/base_feature_provider.h b/chrome/common/extensions/features/base_feature_provider.h
index 389f8acb0649b3b899743923de0e2e07cd82046b..60810c3bed04b59812f72b16ad9d0b55c643a3ed 100644
--- a/chrome/common/extensions/features/base_feature_provider.h
+++ b/chrome/common/extensions/features/base_feature_provider.h
@@ -26,17 +26,11 @@ class BaseFeatureProvider : public FeatureProvider {
   BaseFeatureProvider(const DictionaryValue& root, FeatureFactory factory);
   virtual ~BaseFeatureProvider();
 
-  // Gets an instance for the _api_features.json file that is baked into
-  // Chrome as a resource.
-  static BaseFeatureProvider* GetAPIFeatures();
-
-  // Gets an instance for the _manifest_features.json file that is baked into
-  // Chrome as a resource.
-  static BaseFeatureProvider* GetManifestFeatures();
-
-  // Gets an instance for the _permission_features.json file that is baked into
-  // Chrome as a resource.
-  static BaseFeatureProvider* GetPermissionFeatures();
+  // Use GetFeaturesByName() to get the BaseFeatureProvider for a specific type.
+  // If it is possible that the feature provider will not be used, use
+  // LazyGetFeaturesByName().
+  static BaseFeatureProvider* GetFeaturesByName(const std::string& name);
+  static FeatureProvider* LazyGetFeaturesByName(const std::string& name);

[not at google - send to devlin, 2013/04/10 02:06:22]

Is there really a difference? Can you combine these into a single method (also
I'd call it GetByName) and make that the lazy version?

[cduvall, 2013/04/10 02:26:12]

They're both needed because GetFeaturesByName() returns a BaseFeatureProvider,
which is used in some places for BaseFeatureProvider::GetAllFeatureNames().
LazyGetFeaturesByName() just returns a standard FeatureProvider, which just has
GetFeature().

I renamed to GetByName() and GetBaseFeatureProviderByName(), which is a little
verbose (any better ideas?)

[not at google - send to devlin, 2013/04/10 02:42:13]

Ah ok. Perhaps we should pull GetAllFeatureNames into the FeatureProvider
interface then.

[cduvall, 2013/04/10 02:57:56]

Done, had to take off the const, because it wouldn't work for the
LazyFeatureProvider.

 
   // Returns all features described by this instance.
   std::set<std::string> GetAllFeatureNames() const;