Split the ScopedSubresourceFilterFeatureToggle into two helper classes.

components/subresource_filter/core/browser/subresource_filter_features.h

Index: components/subresource_filter/core/browser/subresource_filter_features.h
diff --git a/components/subresource_filter/core/browser/subresource_filter_features.h b/components/subresource_filter/core/browser/subresource_filter_features.h
index cd3e242d7cda44503491e965a3cb9ccecd82ddfc..b0f5e1c10067e0af88d69198a5e2fedc593aa685 100644
--- a/components/subresource_filter/core/browser/subresource_filter_features.h
+++ b/components/subresource_filter/core/browser/subresource_filter_features.h
@@ -18,8 +18,11 @@ namespace subresource_filter {
 // should operate.
 struct Configuration {
   Configuration();
-  ~Configuration();
+  Configuration(ActivationLevel activation_level,
+                ActivationScope activation_scope,
+                ActivationList activation_list = ActivationList::NONE);
   Configuration(Configuration&&);
+  ~Configuration();
   Configuration& operator=(Configuration&&);
 
   // The maximum degree to which subresource filtering should be activated on
@@ -47,8 +50,8 @@ struct Configuration {
   // be suppressed in the UI.
   bool should_suppress_notifications = false;
 
-  // The ruleset flavor to download through the component updater, or the empty
-  // string if the default ruleset should be used.
+  // The ruleset flavor to download through the component updater. This or the
+  // empty string if the default ruleset should be used.
   std::string ruleset_flavor;
 
   // Whether to whitelist a site when a page loaded from that site is reloaded.
@@ -75,15 +78,16 @@ class ConfigurationList : public base::RefCountedThreadSafe<ConfigurationList> {
 // Retrieves all currently enabled subresource filtering configurations. The
 // configurations are parsed on first access and then the result is cached.
 //
-// In tests, however, the config may change in-between navigations, so callers
-// should not hold on to the result for long.
+// In tests, however, the config may be altered in-between navigations, so
+// callers should not hold on to the result for long.
 scoped_refptr<ConfigurationList> GetActiveConfigurations();
 
 namespace testing {
 
-// Clears the cached active ConfigurationList so that it will be recomputed on
-// next access. Used in tests when the variation parameters are altered.
-void ClearCachedActiveConfigurations();
+// Returns the currently cached active ConfigurationList, if any, and replaces
+// it with |configs|, which may be nullptr to clear the cache.
+scoped_refptr<ConfigurationList> ReplaceCachedActiveConfigurations(

[Charlie Harrison, 2017/04/25 19:36:21]

This is like a get-and-set right? Maybe
GetAndSetActiveConfigurations(scoped_refptr<ConfigurationList> new_configs)?

[engedy, 2017/04/25 20:13:24]

Done.

+    scoped_refptr<ConfigurationList> configs);
 
 }  // namespace testing