[signin] Add DICe flow for account consistency requests.

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 5265026b31479112d9e39507ee06bd414a93b213..ed93da63f3a7c1e2634baeb85b00f7bac4acdeb6 100644
--- a/components/signin/core/browser/BUILD.gn
+++ b/components/signin/core/browser/BUILD.gn
@@ -32,6 +32,10 @@ static_library("browser") {
     "child_account_info_fetcher_android.h",
     "child_account_info_fetcher_impl.cc",
     "child_account_info_fetcher_impl.h",
+    "chrome_connected_header_helper.cc",
+    "chrome_connected_header_helper.h",
+    "dice_header_helper.cc",
+    "dice_header_helper.h",
     "gaia_cookie_manager_service.cc",
     "gaia_cookie_manager_service.h",
     "profile_identity_provider.cc",
@@ -107,6 +111,13 @@ static_library("browser") {
     ]
   }
 
+  if (is_android || is_ios) {
+    sources -= [
+      "dice_header_helper.cc",
+      "dice_header_helper.h",
+    ]
+  }
+
   if (is_android) {
     sources -= [
       "child_account_info_fetcher_impl.cc",