Add initial version of analytics and crash reporting package.

pkg/telemetry/lib/telemetry.dart

Index: pkg/telemetry/lib/telemetry.dart
diff --git a/pkg/telemetry/lib/telemetry.dart b/pkg/telemetry/lib/telemetry.dart
new file mode 100644
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+++ b/pkg/telemetry/lib/telemetry.dart
@@ -0,0 +1,99 @@
+// Copyright (c) 2017, 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.
+
+import 'dart:io';
+
+import 'package:path/path.dart' as path;
+import 'package:usage/src/usage_impl.dart';
+import 'package:usage/src/usage_impl_io.dart';
+import 'package:usage/src/usage_impl_io.dart' as usage_io show getDartVersion;
+import 'package:usage/usage.dart';
+import 'package:usage/usage_io.dart';
+
+final String _dartDirectoryName = '.dart';
+final String _settingsFileName = 'analytics.json';
+
+/// Dart SDK tools with analytics should display this notice.
+///
+/// In addition, they should support displaying the analytics' status, and have
+/// a flag to toggle analytics. This may look something like:
+///
+/// `Analytics are currently enabled (and can be disabled with --no-analytics).`
+final String analyticsNotice =
+    "Dart SDK tools anonymously report feature usage statistics and basic "
+    "crash reports to help improve Dart tools over time. See Google's privacy "
+    "policy: https://www.google.com/intl/en/policies/privacy/.";
+
+/// Create an [Analytics] instance with the given trackingID and
+/// applicationName.
+///
+/// This analytics instance will share a common enablement state with the rest
+/// of the Dart SDK tools.
+Analytics createAnalyticsInstance(String trackingId, String applicationName,
+    {bool disableForSession: false}) {
+  Directory dir = getDartStorageDirectory();
+  if (!dir.existsSync()) {
+    dir.createSync();
+  }
+
+  File file = new File(path.join(dir.path, _settingsFileName));
+  return new _TelemetryAnalytics(
+      trackingId, applicationName, getDartVersion(), file, disableForSession);
+}
+
+/// The directory used to store the analytics settings file.
+///
+/// Typically, the directory is `~/.dart/` (and the settings file is
+/// `analytics.json`).
+Directory getDartStorageDirectory() =>
+    new Directory(path.join(userHomeDir(), _dartDirectoryName));
+
+/// Return the version of the Dart SDK.
+String getDartVersion() => usage_io.getDartVersion();
+
+class _TelemetryAnalytics extends AnalyticsImpl {
+  final bool disableForSession;
+
+  _TelemetryAnalytics(
+    String trackingId,
+    String applicationName,
+    String applicationVersion,
+    File file,
+    this.disableForSession,
+  )
+      : super(
+          trackingId,
+          new IOPersistentProperties.fromFile(file),
+          new IOPostHandler(),
+          applicationName: applicationName,
+          applicationVersion: applicationVersion,
+        ) {
+    final String locale = getPlatformLocale();
+    if (locale != null) {
+      setSessionValue('ul', locale);
+    }
+  }
+
+  @override
+  bool get enabled {
+    if (disableForSession || _isRunningOnBot()) {
+      return false;
+    }
+    return super.enabled;
+  }
+}
+
+bool _isRunningOnBot() {
+  // - https://docs.travis-ci.com/user/environment-variables/
+  // - https://www.appveyor.com/docs/environment-variables/
+  // - CHROME_HEADLESS and BUILDBOT_BUILDERNAME are properties on Chrome infra
+  //   bots.
+  return Platform.environment['TRAVIS'] == 'true' ||
+      Platform.environment['BOT'] == 'true' ||
+      Platform.environment['CONTINUOUS_INTEGRATION'] == 'true' ||
+      Platform.environment['CHROME_HEADLESS'] == '1' ||
+      Platform.environment.containsKey('BUILDBOT_BUILDERNAME') ||
+      Platform.environment.containsKey('APPVEYOR') ||
+      Platform.environment.containsKey('CI');
+}