Introduce subresource_filter::ConfigurationList and make querying it cheap.

components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h

Index: components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h
diff --git a/components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h b/components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h
index f6c4865b96e0a9923623b32caf1c31bd16ba64f5..b7969d7705d01efbf024f6f77a7e6f18659a16fc 100644
--- a/components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h
+++ b/components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h
@@ -17,7 +17,6 @@
 #include "base/time/time.h"
 #include "components/safe_browsing_db/util.h"
 #include "components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.h"
-#include "components/subresource_filter/core/browser/subresource_filter_features.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "ui/base/page_transition_types.h"
 #include "url/gurl.h"
@@ -120,14 +119,6 @@ class ContentSubresourceFilterDriverFactory
     return throttle_manager_.get();
   }
 
-  // TODO(https://crbug.com/708181): Allow tests to change the configuration
-  // after construction (which happens at WebContents creation) but before a
-  // navigation start. Can be removed once the Safe Browsing navigation throttle
-  // handles all activation decisions.
-  void set_configuration_for_testing(Configuration configuration) {
-    configuration_ = std::move(configuration);
-  }
-
   SubresourceFilterClient* client() { return client_.get(); }
 
  private:
@@ -158,8 +149,6 @@ class ContentSubresourceFilterDriverFactory
   void RecordRedirectChainMatchPatternForList(
       ActivationList activation_list) const;
 
-  Configuration configuration_;
-
   std::unique_ptr<SubresourceFilterClient> client_;
 
   std::unique_ptr<ContentSubresourceFilterThrottleManager> throttle_manager_;