Move most importer code to chrome/utility/importer

chrome/browser/bookmarks/DEPS

 include_rules = [
   # Bookmarks is being made into a component (it will end up at
   # //components/bookmarks and not depend on //chrome), so we have these basic
   # rules followed by temporary exceptions.  Please don't add to the list of
   # exceptions!
   "-chrome/browser",
   "+chrome/browser/bookmarks",
   "+chrome/browser/favicon",
   "+chrome/browser/chrome_notification_types.h",
 
   # TODO(kaiwang): Bring this list to zero.
   # Do not add to the list of temporarily-allowed dependencies below,
   # and please do not introduce more #includes of these files.
   "!chrome/browser/history/history_service.h",
   "!chrome/browser/history/history_service_factory.h",
   "!chrome/browser/history/query_parser.h",
   "!chrome/browser/history/url_database.h",
   "!chrome/browser/profiles/incognito_helpers.h",
   "!chrome/browser/profiles/profile.h",
   "!chrome/browser/profiles/startup_task_runner_service.h",
   "!chrome/browser/profiles/startup_task_runner_service_factory.h",
   # Do not add to the list of temporarily-allowed dependencies above,
   # and please do not introduce more #includes of these files.
 ]
+
+specific_include_rules = {
+  # For unit tests, it's fine to include utility process code.
+  '.*test\.cc': [
+    "+chrome/utility/importer/bookmark_html_reader.h",
+  ],
+}