Added PermissionIDSet to APIPermissions

extensions/common/permissions/media_galleries_permission.h

Index: extensions/common/permissions/media_galleries_permission.h
diff --git a/extensions/common/permissions/media_galleries_permission.h b/extensions/common/permissions/media_galleries_permission.h
index dfaed1b05f27fe57c35c245e725cebb96308b553..4bc5794f716b5dca8adfaf6fceea6df879a5f228 100644
--- a/extensions/common/permissions/media_galleries_permission.h
+++ b/extensions/common/permissions/media_galleries_permission.h
@@ -43,6 +43,7 @@ class MediaGalleriesPermission
                  std::vector<std::string>* unhandled_permissions) override;
 
   // APIPermission overrides.
+  PermissionIDSet GetPermissions() const override;
   PermissionMessages GetMessages() const override;
 
   // Permission strings.
@@ -51,6 +52,12 @@ class MediaGalleriesPermission
   static const char kReadPermission[];
   static const char kCopyToPermission[];
   static const char kDeletePermission[];
+
+ private:
+  // TODO(sashab): Once GetMessages() is deprecated, move this logic back into
+  // GetPermissions().
+  void AddMessagesAndPermissions(PermissionIDSet* permission_ids,
+                                 PermissionMessages* permission_messages) const;
 };
 
 }  // namespace extensions