test.dart: Find cdb.exe automatically from depot_tools when running Windows tests

tools/testing/dart/test_configurations.dart

Index: tools/testing/dart/test_configurations.dart
diff --git a/tools/testing/dart/test_configurations.dart b/tools/testing/dart/test_configurations.dart
index 9418bd7d083c2ad0593f82aa16c933cef96cc967..da1d76e192782a680ea8ab4c62ed2278e0ca6794 100644
--- a/tools/testing/dart/test_configurations.dart
+++ b/tools/testing/dart/test_configurations.dart
@@ -7,6 +7,7 @@ library test_configurations;
 import "dart:async";
 import 'dart:io';
 import "dart:math" as math;
+import 'dart:convert';

[zra, 2017/02/06 21:56:41]

alphabetize

[Florian Schneider, 2017/02/06 22:31:46]

Done.

 
 import 'android.dart';
 import "browser_controller.dart";
@@ -54,6 +55,8 @@ final TEST_SUITE_DIRECTORIES = [
   new Path('utils/tests/peg'),
 ];
 
+final VS_TOOLCHAIN_FILE = new Path("build/win_toolchain.json");
+
 Future testConfigurations(List<Map> configurations) async {
   var startTime = new DateTime.now();
   // Extract global options from first configuration.
@@ -294,6 +297,13 @@ Future testConfigurations(List<Map> configurations) async {
     await Future.wait(serverFutures);
   }
 
+  if (Platform.isWindows) {
+    // When running tests on Windows, use cdb from depot_tools to dump
+    // stack traces of tests timing out.
+    var text = await new File(VS_TOOLCHAIN_FILE.toNativePath()).readAsString();
+    firstConf['win_sdk_path'] = JSON.decode(text)['win_sdk'];
+  }
+
   // [firstConf] is needed here, since the ProcessQueue needs to know the
   // settings of 'noBatch' and 'local_ip'
   new ProcessQueue(