Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/test/lib/src/util/dart.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library test.util.dart;
+
+import 'dart:async';
+import 'dart:isolate';
+
+import 'package:analyzer/analyzer.dart';
+import 'package:source_span/source_span.dart';
+
+import 'string_literal_iterator.dart';
+
+/// Runs [code] in an isolate.
+///
+/// [code] should be the contents of a Dart entrypoint. It may contain imports;
+/// they will be resolved in the same context as the host isolate. [message] is
+/// passed to the [main] method of the code being run; the caller is responsible
+/// for using this to establish communication with the isolate.
+///
+/// [packageRoot] controls the package root of the isolate. It may be either a
+/// [String] or a [Uri].
+Future<Isolate> runInIsolate(String code, message, {packageRoot,
+    bool checked}) async {
+  if (packageRoot is String) packageRoot = Uri.parse(packageRoot);
+
+  return await Isolate.spawnUri(
+      Uri.parse('data:application/dart;charset=utf-8,' + Uri.encodeFull(code)),
+      [],
+      message,
+      packageRoot: packageRoot,
+      checked: checked);
+}
+
+// TODO(nweiz): Move this into the analyzer once it starts using SourceSpan
+// (issue 22977).
+/// Takes a span whose source is the value of a string that has been parsed from
+/// a Dart file and returns the corresponding span from within that Dart file.
+///
+/// For example, suppose a Dart file contains `@Eval("1 + a")`. The
+/// [StringLiteral] `"1 + a"` is extracted; this is [context]. Its contents are
+/// then parsed, producing an error pointing to [span]:
+///
+///     line 1, column 5:
+///     1 + a
+///         ^
+///
+/// This span isn't very useful, since it only shows the location within the
+/// [StringLiteral]'s value. So it's passed to [contextualizeSpan] along with
+/// [context] and [file] (which contains the source of the entire Dart file),
+/// which then returns:
+///
+///     line 4, column 12 of file.dart:
+///     @Eval("1 + a")
+///                ^
+///
+/// This properly handles multiline literals, adjacent literals, and literals
+/// containing escape sequences. It does not support interpolated literals.
+///
+/// This will return `null` if [context] contains an invalid string or does not
+/// contain [span].
+SourceSpan contextualizeSpan(SourceSpan span, StringLiteral context,
+    SourceFile file) {
+  var contextRunes = new StringLiteralIterator(context)..moveNext();
+
+  for (var i = 0; i < span.start.offset; i++) {
+    if (!contextRunes.moveNext()) return null;
+  }
+
+  var start = contextRunes.offset;
+  for (var spanRune in span.text.runes) {
+    if (spanRune != contextRunes.current) return null;
+    contextRunes.moveNext();
+  }
+
+  return file.span(start, contextRunes.offset);
+}