Track missing dartdocs (#10213)

This will help catch when we accidentally break --dartdocs.

dev/devicelab/bin/tasks/dartdocs.dart

+// Copyright 2017 The Chromium Authors. 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:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:flutter_devicelab/framework/framework.dart';
+import 'package:flutter_devicelab/framework/utils.dart';
+
+Future<Null> main() async {
+  await task(() async {
+    final Stopwatch clock = new Stopwatch()..start();
+    final Process analysis = await startProcess(
+      'flutter',
+      <String>['analyze', '--flutter-repo', '--dartdocs'],
+      workingDirectory: flutterDirectory.path,
+    );
+    int publicMembers = 0;
+    int otherErrors = 0;
+    int otherLines = 0;
+    await for (String entry in analysis.stderr.transform(UTF8.decoder).transform(const LineSplitter())) {
+      print('analyzer stderr: $entry');
+      if (entry.startsWith('[lint] Document all public members')) {
+        publicMembers += 1;
+      } else if (entry.startsWith('[')) {
+        otherErrors += 1;
+      } else if (entry.startsWith('(Ran in ')) {
+        // ignore this line
+      } else {
+        otherLines += 1;
+      }
+    }
+    await for (String entry in analysis.stdout.transform(UTF8.decoder).transform(const LineSplitter())) {
+      print('analyzer stdout: $entry');
+      if (entry == 'Building flutter tool...') {
+        // ignore this line
+      } else if (entry.startsWith('Analyzing ')) {
+        // ignore this line
+      } else {
+        otherLines += 1;
+      }
+    }
+    final int result = await analysis.exitCode;
+    clock.stop();
+    if (publicMembers == 0 && otherErrors == 0 && result != 0)
+      throw new Exception('flutter analyze exited with unexpected error code $result');
+    if (publicMembers != 0 && otherErrors != 0 && result == 0)
+      throw new Exception('flutter analyze exited with successful status code despite reporting errors');
+    if (otherLines != 0)
+      throw new Exception('flutter analyze had unexpected output (we saw $otherLines unexpected line${ otherLines == 1 ? "" : "s" })');
+    final Map<String, dynamic> data = <String, dynamic>{
+      'members_missing_dartdocs': publicMembers,
+      'analysis_errors': otherErrors,
+      'elapsed_time_ms': clock.elapsedMilliseconds,
+    };
+    return new TaskResult.success(data, benchmarkScoreKeys: data.keys.toList());
+  });
+}

dev/devicelab/manifest.yaml

@@ -75,6 +75,12 @@ tasks:
     stage: devicelab
     required_agent_capabilities: ["has-android-device"]
 
+  dartdocs:
+    description: >
+      Tracks how many members are still lacking documentation.
+    stage: devicelab
+    required_agent_capabilities: ["has-android-device"]
+
   # Android on-device tests
 
   complex_layout_scroll_perf__timeline_summary:
@@ -190,14 +196,14 @@ tasks:
 #      Measures the startup time of the Flutter Gallery app on iOS.
 #    stage: devicelab_ios
 #    required_agent_capabilities: ["has-ios-device"]
-#    flaky: true    
+#    flaky: true
 
 #  complex_layout_ios__start_up:
 #    description: >
 #      Measures the startup time of the Complex Layout sample app on iOS.
 #    stage: devicelab_ios
 #    required_agent_capabilities: ["has-ios-device"]
-#    flaky: true    
+#    flaky: true
 
   flutter_gallery_ios__transition_perf:
     description: >
@@ -225,7 +231,7 @@ tasks:
 #      Verifies that Flutter View can be used from an iOS project.
 #    stage: devicelab_ios
 #    required_agent_capabilities: ["has-ios-device"]
-#    flaky: true    
+#    flaky: true
 
   integration_ui_ios:
     description: >