[sync] Purge directory data when migrating to USS

components/sync/base/model_type.h

Index: components/sync/base/model_type.h
diff --git a/components/sync/base/model_type.h b/components/sync/base/model_type.h
index eb8365323f7beb9a8e4f57afde54870ea2e6b010..c6d544f5fd5bdf582b7eba22a4bd7685dabc4c52 100644
--- a/components/sync/base/model_type.h
+++ b/components/sync/base/model_type.h
@@ -12,6 +12,7 @@
 #include <string>
 
 #include "base/logging.h"
+#include "components/reading_list/core/reading_list_enable_flags.h"
 #include "components/sync/base/enum_set.h"
 
 namespace base {
@@ -201,11 +202,26 @@ ModelTypeSet ProtocolTypes();
 // These are the normal user-controlled types. This is to distinguish from
 // ControlTypes which are always enabled.  Note that some of these share a
 // preference flag, so not all of them are individually user-selectable.
-ModelTypeSet UserTypes();
+constexpr ModelTypeSet UserTypes() {
+  return ModelTypeSet::FromRange(FIRST_USER_MODEL_TYPE, LAST_USER_MODEL_TYPE);
+}
 
 // These are the user-selectable data types.
-ModelTypeSet UserSelectableTypes();
-bool IsUserSelectableType(ModelType model_type);
+constexpr ModelTypeSet UserSelectableTypes() {
+  return ModelTypeSet({
+    BOOKMARKS, PREFERENCES, PASSWORDS, AUTOFILL, THEMES, TYPED_URLS, EXTENSIONS,
+        APPS,
+#if BUILDFLAG(ENABLE_READING_LIST)
+        READING_LIST,
+#endif
+        PROXY_TABS
+  });
+}
+
+constexpr bool IsUserSelectableType(ModelType model_type) {
+  return UserSelectableTypes().Has(model_type);
+}
+
 ModelTypeNameMap GetUserSelectableTypeNameMap();
 
 // This is the subset of UserTypes() that can be encrypted.
@@ -213,12 +229,9 @@ ModelTypeSet EncryptableUserTypes();
 
 // This is the subset of UserTypes() that have priority over other types.  These
 // types are synced before other user types and are never encrypted.
-ModelTypeSet PriorityUserTypes();
-
-// Proxy types are placeholder types for handling implicitly enabling real
-// types. They do not exist at the server, and are simply used for
-// UI/Configuration logic.
-ModelTypeSet ProxyTypes();
+constexpr ModelTypeSet PriorityUserTypes() {
+  return ModelTypeSet({DEVICE_INFO, PRIORITY_PREFERENCES});
+}
 
 // Returns a list of all control types.
 //
@@ -230,12 +243,24 @@ ModelTypeSet ProxyTypes();
 // - Their contents are not encrypted automatically.
 // - They support custom update application and conflict resolution logic.
 // - All change processing occurs on the sync thread (GROUP_PASSIVE).
-ModelTypeSet ControlTypes();
+constexpr ModelTypeSet ControlTypes() {
+  return ModelTypeSet::FromRange(FIRST_CONTROL_MODEL_TYPE,
+                                 LAST_CONTROL_MODEL_TYPE);
+}
+
+// Proxy types are placeholder types for handling implicitly enabling real
+// types. They do not exist at the server, and are simply used for
+// UI/Configuration logic.
+constexpr ModelTypeSet ProxyTypes() {
+  return ModelTypeSet::FromRange(FIRST_PROXY_TYPE, LAST_PROXY_TYPE);
+}
 
 // Returns true if this is a control type.
 //
 // See comment above for more information on what makes these types special.
-bool IsControlType(ModelType model_type);
+constexpr bool IsControlType(ModelType model_type) {
+  return ControlTypes().Has(model_type);
+}
 
 // Core types are those data types used by sync's core functionality (i.e. not
 // user data types). These types are always enabled, and include ControlTypes().