Implementation of beginning of Declarative Web Request API backend

chrome/browser/extensions/api/declarative/url_matcher.cc

Index: chrome/browser/extensions/api/declarative/url_matcher.cc
diff --git a/chrome/browser/extensions/api/declarative/url_matcher.cc b/chrome/browser/extensions/api/declarative/url_matcher.cc
index af8e4657f652f4d014646a48f08433fc0d4ae14f..91ee8b55c7ac3468def1e2b71ab4fdf938cd3d61 100644
--- a/chrome/browser/extensions/api/declarative/url_matcher.cc
+++ b/chrome/browser/extensions/api/declarative/url_matcher.cc
@@ -445,6 +445,10 @@ void URLMatcher::RemoveConditionSets(
   UpdateInternalDatastructures();
 }
 
+void URLMatcher::ClearUnusedConditionSets() {
+  UpdateConditionFactory();
+}
+
 std::set<URLMatcherConditionSet::ID> URLMatcher::MatchURL(const GURL& url) {
   // Find all IDs of SubstringPatterns that match |url|.
   // See URLMatcherConditionFactory for the canonicalization of URLs and the