Use a two-part data format version in IndexedDB metadata.

content/common/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("features.gni")
 import("//build/buildflag_header.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//media/media_options.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
@@ skipping 138 matching lines @@
     "frame_replication_state.h",
     "generic_shared_memory_id_generator.cc",
     "generic_shared_memory_id_generator.h",
     "gin_java_bridge_messages.h",
     "gpu_host_messages.h",
     "host_shared_bitmap_manager.cc",
     "host_shared_bitmap_manager.h",
     "in_process_child_thread_params.cc",
     "in_process_child_thread_params.h",
     "indexed_db/indexed_db_constants.h",
+    "indexed_db/indexed_db_data_format_version.h",
     "indexed_db/indexed_db_key.cc",
     "indexed_db/indexed_db_key.h",
     "indexed_db/indexed_db_key_path.cc",
     "indexed_db/indexed_db_key_path.h",
     "indexed_db/indexed_db_key_range.cc",
     "indexed_db/indexed_db_key_range.h",
     "indexed_db/indexed_db_metadata.cc",
     "indexed_db/indexed_db_metadata.h",
     "indexed_db/indexed_db_struct_traits.cc",
     "indexed_db/indexed_db_struct_traits.h",
@@ skipping 471 matching lines @@
     "//url/mojo:url_mojom_origin",
   ]
 
   overridden_deps = [ "//ipc:mojom" ]
   component_deps = [ "//ipc" ]
 
   export_class_attribute = "CONTENT_EXPORT"
   export_define = "CONTENT_IMPLEMENTATION=1"
   export_header = "content/common/content_export.h"
 }