Dart: Rebase generated imports from the SDK to the SDK base directory.

mojo/services/surfaces/public/interfaces/BUILD.gn

Index: mojo/services/surfaces/public/interfaces/BUILD.gn
diff --git a/mojo/services/surfaces/public/interfaces/BUILD.gn b/mojo/services/surfaces/public/interfaces/BUILD.gn
index 7902a7a98ea43393ad05e6bb00b66a3ba1a7af0a..36c870771109dfedabb86ebd04d7a0222fc3a313 100644
--- a/mojo/services/surfaces/public/interfaces/BUILD.gn
+++ b/mojo/services/surfaces/public/interfaces/BUILD.gn
@@ -20,10 +20,14 @@ mojom("interfaces") {
     "../../../gpu/public/interfaces",
     "../../../native_viewport/public/interfaces",
   ]
+
+  import_from = mojo_root
 }
 
 mojom("surface_id") {
   sources = [
     "surface_id.mojom",
   ]
+
+  import_from = mojo_root
 }