Address additional analysis issues in the observatory codebase.

runtime/observatory/tests/service/service_test_common.dart

 // Copyright (c) 2016, 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 service_test_common;
 
 import 'dart:async';
-import 'dart:io' show Platform;
+import 'dart:io' show File, Platform;
+
 import 'package:observatory/models.dart' as M;
 import 'package:observatory/service_common.dart';
 import 'package:unittest/unittest.dart';
 
 typedef Future IsolateTest(Isolate isolate);
 typedef Future VMTest(VM vm);
 
 Map<String, StreamSubscription> streamSubscriptions = {};
 
+class ScriptLineParser {

[rmacnak, 2017/06/12 16:02:12]

Awesome!

+  List<String> lines;
+
+  ScriptLineParser(Uri scriptUri) {
+    String content = new File(scriptUri.toFilePath()).readAsStringSync();
+    lines = content.split('\n');
+  }
+
+  int lineFor(String commentContent) {
+    String match1 = '// $commentContent';
+    String match2 = '/* $commentContent */';
+
+    for (int i = 0; i < lines.length; i++) {
+      if (lines[i].contains(match1) || lines[i].contains(match2)) {
+        // return the 1-based line number
+        return i + 1;
+      }
+    }
+
+    return -1;
+  }
+}
+
 Future subscribeToStream(VM vm, String streamName, onEvent) async {
   assert(streamSubscriptions[streamName] == null);
 
   Stream stream = await vm.getEventStream(streamName);
   StreamSubscription subscription = stream.listen(onEvent);
   streamSubscriptions[streamName] = subscription;
 }
 
 Future cancelStreamSubscription(String streamName) async {
   StreamSubscription subscription = streamSubscriptions[streamName];
@@ skipping 497 matching lines @@
   if (!isKernel()) {
     nonKernelFunction();
   }
 }
 
 void kernelExecute(Function kernelFunction) {
   if (isKernel()) {
     kernelFunction();
   }
 }