Remove *.mojom.dart from //{,mojo/public/dart/}.gitignore, stop copying during build

mojo/public/tools/dart_pkg.py

Index: mojo/public/tools/dart_pkg.py
diff --git a/mojo/public/tools/dart_pkg.py b/mojo/public/tools/dart_pkg.py
index 34a1a6ca6fbe83b3fe0494cfc318b268ed309d07..2f43d249ed779e42ae080110e340ee8474d0f799 100755
--- a/mojo/public/tools/dart_pkg.py
+++ b/mojo/public/tools/dart_pkg.py
@@ -313,17 +313,6 @@ def main():
   package_path = os.path.join(args.package_root, args.package_name)
   link(lib_path, package_path)
 
-  # TODO(zra): Remove when bindings are generated by the mojom package and
-  # checked in.
-  # Copy generated bindings back to the source directory.
-  if not args.read_only:
-    generated_bindings = list_files(lib_path, mojom_dart_filter)
-    for binding in generated_bindings:
-      lib_rel_path = os.path.relpath(binding, lib_path)
-      dest = os.path.join(common_source_prefix, 'lib', lib_rel_path)
-      remove_if_exists(dest)
-      copy(binding, dest)
-
   # Link dart-pkg/$package/packages to dart-pkg/packages
   link_if_possible(args.package_root, target_packages_dir)