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

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

Index: mojo/public/dart/third_party/test/lib/src/util/stack_trace_mapper.dart
diff --git a/mojo/public/dart/third_party/test/lib/src/util/stack_trace_mapper.dart b/mojo/public/dart/third_party/test/lib/src/util/stack_trace_mapper.dart
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index 0000000000000000000000000000000000000000..30d6e75918c9d130748108a71e9800be3b4648b4
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@@ -0,0 +1,30 @@
+// 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.stack_trace_mapper;
+
+import 'package:source_map_stack_trace/source_map_stack_trace.dart' as mapper;
+import 'package:source_maps/source_maps.dart';
+
+/// A class for mapping JS stack traces to Dart stack traces using source maps.
+class StackTraceMapper {
+  /// The parsed source map.
+  final Mapping _mapping;
+
+  /// The URI of the package root, as passed to dart2js.
+  final Uri _packageRoot;
+
+  /// The URI of the SDK root from which dart2js loaded its sources.
+  final Uri _sdkRoot;
+
+  StackTraceMapper(String contents, {Uri mapUrl, Uri packageRoot, Uri sdkRoot})
+    : _mapping = parse(contents, mapUrl: mapUrl),
+      _packageRoot = packageRoot,
+      _sdkRoot = sdkRoot;
+
+  /// Converts [trace] into a Dart stack trace.
+  StackTrace mapStackTrace(StackTrace trace) =>
+      mapper.mapStackTrace(_mapping, trace,
+          packageRoot: _packageRoot, sdkRoot: _sdkRoot);
+}