Refactor AO2TS to make it easier to componentize.

components/signin/core/browser/BUILD.gn

Index: components/signin/core/browser/BUILD.gn
diff --git a/components/signin/core/browser/BUILD.gn b/components/signin/core/browser/BUILD.gn
index f8307713514e0be8e864a33303b737ac82040996..d3ca92c338eb44b8470e586db6f648cb22e96f8e 100644
--- a/components/signin/core/browser/BUILD.gn
+++ b/components/signin/core/browser/BUILD.gn
@@ -14,8 +14,6 @@ static_library("browser") {
     "device_activity_fetcher.h",
     "gaia_cookie_manager_service.cc",
     "gaia_cookie_manager_service.h",
-    "mutable_profile_oauth2_token_service.cc",
-    "mutable_profile_oauth2_token_service.h",
     "profile_oauth2_token_service.cc",
     "profile_oauth2_token_service.h",
     "refresh_token_annotation_request.cc",
@@ -59,13 +57,6 @@ static_library("browser") {
     "//components/webdata/common",
   ]
 
-  if (is_android) {
-    sources -= [
-      "mutable_profile_oauth2_token_service.cc",
-      "mutable_profile_oauth2_token_service.h",
-    ]
-  }
-
   if (is_chromeos) {
     sources -= [ "signin_manager.cc" ]
   }