Query API: Introduces an OfflinePageModelQuery object.

components/offline_pages/client_policy_controller.cc

Index: components/offline_pages/client_policy_controller.cc
diff --git a/components/offline_pages/client_policy_controller.cc b/components/offline_pages/client_policy_controller.cc
index 23772308ec9f5490ddc75e9ed79469a727f75a0c..81ef09e32e59322cf5c0d1acad4f2a269328625c 100644
--- a/components/offline_pages/client_policy_controller.cc
+++ b/components/offline_pages/client_policy_controller.cc
@@ -4,6 +4,7 @@
 
 #include "components/offline_pages/client_policy_controller.h"
 
+#include <set>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
@@ -84,6 +85,18 @@ const OfflinePageClientPolicy& ClientPolicyController::GetPolicy(
   return policies_.at(kDefaultNamespace);
 }
 
+std::vector<std::string> ClientPolicyController::GetAllNamespacesExcept(
+    const std::vector<std::string>& exceptions) const {
+  std::set<std::string> exception_set(exceptions.begin(), exceptions.end());
+  std::vector<std::string> result;
+  for (const auto& policy_item : policies_) {
+    if (exception_set.count(policy_item.first) == 0)
+      result.emplace_back(policy_item.first);
+  }
+
+  return result;
+}
+
 bool ClientPolicyController::IsRemovedOnCacheReset(
     const std::string& name_space) const {
   return GetPolicy(name_space).feature_policy.is_removed_on_cache_reset;