Enable fetching of admin policies for login screen apps

components/policy/core/common/schema_registry.h

Index: components/policy/core/common/schema_registry.h
diff --git a/components/policy/core/common/schema_registry.h b/components/policy/core/common/schema_registry.h
index 82e16f8a958c2b1d8e054f7a6f9c0bf1d0c97661..35c63e09aa62fee47bde2141553306ad1d9f8ece 100644
--- a/components/policy/core/common/schema_registry.h
+++ b/components/policy/core/common/schema_registry.h
@@ -132,9 +132,12 @@ class POLICY_EXPORT ForwardingSchemaRegistry
       public SchemaRegistry::Observer,
       public SchemaRegistry::InternalObserver {
  public:
+  // If |forward_readiness| is true, then this registry will become ready as
+  // soon as the wrapped registry gets ready.
+  //
   // This registry will stop updating its SchemaMap when |wrapped| is
   // destroyed.
-  explicit ForwardingSchemaRegistry(SchemaRegistry* wrapped);
+  ForwardingSchemaRegistry(SchemaRegistry* wrapped, bool forward_readiness);
   ~ForwardingSchemaRegistry() override;
 
   // SchemaRegistry:
@@ -144,12 +147,16 @@ class POLICY_EXPORT ForwardingSchemaRegistry
 
   // SchemaRegistry::Observer:
   void OnSchemaRegistryUpdated(bool has_new_schemas) override;
+  void OnSchemaRegistryReady() override;
 
   // SchemaRegistry::InternalObserver:
   void OnSchemaRegistryShuttingDown(SchemaRegistry* registry) override;
 
  private:
+  void UpdateReadiness();
+
   SchemaRegistry* wrapped_;
+  bool forward_readiness_;
 
   DISALLOW_COPY_AND_ASSIGN(ForwardingSchemaRegistry);
 };