[CrOS Tether] Create CryptAuthService and implement it via ChromeCryptAuthService and ChromeCryptAuthServiceFactory.

These classes are currently unused. In a follow-up CL, I will integrate the new service into Chrome and refactor some of the code shared between this new class and the various EasyUnlock classes which share similar functionality.

BUG=672263

Review-Url: https://codereview.chromium.org/2739053002
Cr-Commit-Position: refs/heads/master@{#457194}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index b3682d0..d8af69c 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -1895,7 +1895,6 @@
       "//chrome/common/extensions/api",
       "//chrome/common/extensions/api:api_registration",
       "//chrome/common/extensions/api:extensions_features",
-      "//components/cryptauth",
       "//components/drive",
       "//components/proximity_auth/ble",
       "//extensions/components/javascript_dialog_extensions_client",
@@ -3129,6 +3128,10 @@
       "chrome_browser_main_posix.h",
       "chrome_process_singleton.cc",
       "chrome_process_singleton.h",
+      "cryptauth/chrome_cryptauth_service.cc",
+      "cryptauth/chrome_cryptauth_service.h",
+      "cryptauth/chrome_cryptauth_service_factory.cc",
+      "cryptauth/chrome_cryptauth_service_factory.h",
       "custom_handlers/register_protocol_handler_permission_request.cc",
       "custom_handlers/register_protocol_handler_permission_request.h",
       "custom_home_pages_table_model.cc",
@@ -3506,6 +3509,8 @@
       "//chrome/browser/policy:path_parser",
       "//chrome/browser/profile_resetter:profile_reset_report_proto",
       "//chrome/common/importer:interfaces",
+      "//components/cryptauth",
+      "//components/cryptauth/proto",
       "//components/feedback",
       "//components/web_modal",
       "//device/battery",