Fix the build issue.

https://ci.chromium.org/p/chromium/builders/ci/Libfuzzer%20Upload%20Chrome%20OS%20ASan/29774

TBR=sky@chromium.org
TBR=agawronska@chromium.org

BUG=1060430

Change-Id: I0608315ef2b4d8991e6deacd8282a88efc7b4e52
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2096333Reviewed-by: Nancy Wang <nancylingwang@chromium.org>
Commit-Queue: Nancy Wang <nancylingwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749058}

chrome/browser/BUILD.gn

@@ -5613,6 +5613,7 @@ grit("resources") {
       "//chrome/browser/resources/chromeos/emulator:polymer3_elements",
       "//chrome/browser/resources/chromeos/set_time_dialog:polymer3_elements",
       "//chrome/browser/resources/chromeos/smb_shares:polymer3_elements",
+      "//chrome/browser/supervised_user:supervised_user_unscaled_resources",
       "//chrome/browser/ui/webui/chromeos/add_supervision:mojo_bindings_js",
       "//chrome/browser/ui/webui/chromeos/crostini_installer:mojo_bindings_js",
       "//chrome/browser/ui/webui/chromeos/crostini_upgrader:mojo_bindings_js",

chrome/browser/supervised_user/BUILD.gn

@@ -11,4 +11,9 @@ grit("supervised_user_unscaled_resources") {
     "supervised_user_unscaled_resources.pak",
   ]
   output_dir = "$root_gen_dir/chrome/browser/supervised_user"
+
+  grit_flags = [
+    "-E",
+    "root_gen_dir=" + rebase_path(root_gen_dir, root_build_dir),
+  ]
 }