Yes. You need call 'GetAllPreferences(true)' on context request object with true parameter.
Some kind of magic happened - i got results after answer on forum =)
Debug output:
all preferences in global request context 26
key "apps" value ""
value type is dictionary
valueDictionary key "fullscreen" valueDictionary value ""
key "auth" value ""
value type is dictionary
valueDictionary key "gssapi_library_name" valueDictionary value ""
valueDictionary key "negotiate_delegate_whitelist" valueDictionary value ""
valueDictionary key "server_whitelist" valueDictionary value ""
key "browser" value ""
value type is dictionary
valueDictionary key "enable_spellchecking" valueDictionary value ""
valueDictionary key "last_known_google_url" valueDictionary value "https://www.google.com/"
valueDictionary key "last_prompted_google_url" valueDictionary value ""
key "content_settings_window" value ""
value type is dictionary
valueDictionary key "last_tab_index" valueDictionary value ""
key "devtools" value ""
value type is dictionary
valueDictionary key "preferences" valueDictionary value ""
key "disable_3d_apis" value ""
key "enable_a_ping" value ""
key "enable_do_not_track" value ""
key "enable_referrers" value ""
key "extensions" value ""
value type is dictionary
valueDictionary key "allowed_install_sites" valueDictionary value ""
valueDictionary key "allowed_types" valueDictionary value ""
valueDictionary key "autoupdate" valueDictionary value ""
valueDictionary key "blacklistupdate" valueDictionary value ""
valueDictionary key "corrupted_disable_count" valueDictionary value ""
valueDictionary key "install" valueDictionary value ""
valueDictionary key "install_signature" valueDictionary value ""
valueDictionary key "last_chrome_version" valueDictionary value ""
valueDictionary key "settings" valueDictionary value ""
valueDictionary key "storage" valueDictionary value ""
valueDictionary key "theme" valueDictionary value ""
valueDictionary key "toolbar" valueDictionary value ""
valueDictionary key "toolbarsize" valueDictionary value ""
key "fullscreen" value ""
value type is dictionary
valueDictionary key "allowed" valueDictionary value ""
key "intl" value ""
value type is dictionary
valueDictionary key "accept_languages" valueDictionary value "ru-RU,ru,en-US,en"
valueDictionary key "charset_default" valueDictionary value "windows-1251"
key "media" value ""
value type is dictionary
valueDictionary key "default_audio_capture_device" valueDictionary value ""
valueDictionary key "default_video_capture_Device" valueDictionary value ""
key "native_messaging" value ""
value type is dictionary
valueDictionary key "blacklist" valueDictionary value ""
valueDictionary key "user_level_hosts" valueDictionary value ""
valueDictionary key "whitelist" valueDictionary value ""
key "net" value ""
value type is dictionary
valueDictionary key "network_prediction_options" valueDictionary value ""
key "partition" value ""
value type is dictionary
valueDictionary key "default_zoom_level" valueDictionary value ""
valueDictionary key "per_host_zoom_levels" valueDictionary value ""
key "plugins" value ""
value type is dictionary
valueDictionary key "allow_outdated" valueDictionary value ""
valueDictionary key "always_authorize" valueDictionary value ""
key "printing" value ""
value type is dictionary
valueDictionary key "enabled" valueDictionary value ""
key "profile" value ""
value type is dictionary
valueDictionary key "block_third_party_cookies" valueDictionary value ""
valueDictionary key "content_settings" valueDictionary value ""
valueDictionary key "default_content_setting_values" valueDictionary value ""
valueDictionary key "managed_auto_select_certificate_for_urls" valueDictionary value ""
valueDictionary key "managed_cookies_allowed_for_urls" valueDictionary value ""
valueDictionary key "managed_cookies_blocked_for_urls" valueDictionary value ""
valueDictionary key "managed_cookies_sessiononly_for_urls" valueDictionary value ""
valueDictionary key "managed_default_content_settings" valueDictionary value ""
valueDictionary key "managed_images_allowed_for_urls" valueDictionary value ""
valueDictionary key "managed_images_blocked_for_urls" valueDictionary value ""
valueDictionary key "managed_javascript_allowed_for_urls" valueDictionary value ""
valueDictionary key "managed_javascript_blocked_for_urls" valueDictionary value ""
valueDictionary key "managed_notifications_allowed_for_urls" valueDictionary value ""
valueDictionary key "managed_notifications_blocked_for_urls" valueDictionary value ""
valueDictionary key "managed_plugins_allowed_for_urls" valueDictionary value ""
valueDictionary key "managed_plugins_blocked_for_urls" valueDictionary value ""
valueDictionary key "managed_popups_allowed_for_urls" valueDictionary value ""
valueDictionary key "managed_popups_blocked_for_urls" valueDictionary value ""
key "proxy" value ""
value type is dictionary
valueDictionary key "mode" valueDictionary value "system"
valueDictionary key "pac_https_url_stripping_enabled" valueDictionary value ""
key "select_file_dialogs" value ""
value type is dictionary
valueDictionary key "allowed" valueDictionary value ""
key "settings" value ""
value type is dictionary
valueDictionary key "a11y" valueDictionary value ""
valueDictionary key "force_google_safesearch" valueDictionary value ""
valueDictionary key "privacy" valueDictionary value ""
key "spellcheck" value ""
value type is dictionary
valueDictionary key "dictionaries" valueDictionary value ""
valueDictionary key "dictionary" valueDictionary value "ru"
valueDictionary key "use_spelling_service" valueDictionary value ""
key "updateclientdata" value ""
value type is dictionary
key "webkit" value ""
value type is dictionary
valueDictionary key "webprefs" valueDictionary value ""
key "webrtc" value ""
value type is dictionary
valueDictionary key "ip_handling_policy" valueDictionary value "default"
valueDictionary key "multiple_routes_enabled" valueDictionary value ""
valueDictionary key "nonproxied_udp_enabled" valueDictionary value ""
valueDictionary key "udp_port_range" valueDictionary value ""