Store the async-await compiled pub code directly in the repo.

sdk/lib/_internal/pub_generated/lib/src/ascii_tree.dart

+library pub.ascii_tree;
+import 'package:path/path.dart' as path;
+import 'log.dart' as log;
+import 'utils.dart';
+String fromFiles(List<String> files, {String baseDir, bool showAllChildren}) {
+  var root = {};
+  for (var file in files) {
+    if (baseDir != null) file = path.relative(file, from: baseDir);
+    var parts = path.split(file);
+    var directory = root;
+    for (var part in path.split(file)) {
+      directory = directory.putIfAbsent(part, () => {});
+    }
+  }
+  return fromMap(root, showAllChildren: showAllChildren);
+}
+String fromMap(Map map, {bool showAllChildren}) {
+  var buffer = new StringBuffer();
+  _draw(buffer, "", null, map, showAllChildren: showAllChildren);
+  return buffer.toString();
+}
+void _drawLine(StringBuffer buffer, String prefix, bool isLastChild,
+    String name) {
+  buffer.write(prefix);
+  if (name != null) {
+    if (isLastChild) {
+      buffer.write(log.gray("'-- "));
+    } else {
+      buffer.write(log.gray("|-- "));
+    }
+  }
+  buffer.writeln(name);
+}
+String _getPrefix(bool isRoot, bool isLast) {
+  if (isRoot) return "";
+  if (isLast) return "    ";
+  return log.gray("|   ");
+}
+void _draw(StringBuffer buffer, String prefix, String name, Map children,
+    {bool showAllChildren, bool isLast: false}) {
+  if (showAllChildren == null) showAllChildren = false;
+  if (name != null) _drawLine(buffer, prefix, isLast, name);
+  var childNames = ordered(children.keys);
+  drawChild(bool isLastChild, String child) {
+    var childPrefix = _getPrefix(name == null, isLast);
+    _draw(
+        buffer,
+        '$prefix$childPrefix',
+        child,
+        children[child],
+        showAllChildren: showAllChildren,
+        isLast: isLastChild);
+  }
+  if (name == null || showAllChildren || childNames.length <= 10) {
+    for (var i = 0; i < childNames.length; i++) {
+      drawChild(i == childNames.length - 1, childNames[i]);
+    }
+  } else {
+    drawChild(false, childNames[0]);
+    drawChild(false, childNames[1]);
+    drawChild(false, childNames[2]);
+    buffer.write(prefix);
+    buffer.write(_getPrefix(name == null, isLast));
+    buffer.writeln(log.gray('| (${childNames.length - 6} more...)'));
+    drawChild(false, childNames[childNames.length - 3]);
+    drawChild(false, childNames[childNames.length - 2]);
+    drawChild(true, childNames[childNames.length - 1]);
+  }
+}