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

mojo/public/interfaces/application/BUILD.gn

Index: mojo/public/interfaces/application/BUILD.gn
diff --git a/mojo/public/interfaces/application/BUILD.gn b/mojo/public/interfaces/application/BUILD.gn
index 5b15344c5071309d650162230f4a7cafb3a10c5e..32a6987b3587bdb39f62e572639e5cd0339306a0 100644
--- a/mojo/public/interfaces/application/BUILD.gn
+++ b/mojo/public/interfaces/application/BUILD.gn
@@ -12,8 +12,8 @@ mojom("application") {
     "shell.mojom",
   ]
 
-  # This base dir ensures that Dart's Mojo SDK can be imported with, e.g.,
+  # The import_from ensures that Dart's Mojo SDK can be imported with, e.g.,
   # import 'package:mojo/public/dart/core.dart' even when the Mojo SDK lives
   # somewhere else in the source tree.
-  base_dir = mojo_root
+  import_from = mojo_root
 }