Fix analyzer errors/warnings for Pub.

utils/tests/pub/test_pub.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Test infrastructure for testing pub. Unlike typical unit tests, most pub
  * tests are integration tests that stage some stuff on the file system, run
  * pub, and then validate the results. This library provides an API to build
  * tests like that.
  */
@@ skipping 1406 matching lines @@
       var process = _process.value;
       process.kill();
       process.stdout.close();
       process.stderr.close();
     });
   }
 
   /// Reads the next line of stdout from the process.
   Future<String> nextLine() {
     return _scheduleValue((_) {
-      return timeout(_stdout.chain(readLine), _SCHEDULE_TIMEOUT,
+      return timeout(_stdout.chain((stream) => readLine(stream)),
+          _SCHEDULE_TIMEOUT,
           "waiting for the next stdout line from process $name");
     });
   }
 
   /// Reads the next line of stderr from the process.
   Future<String> nextErrLine() {
     return _scheduleValue((_) {
-      return timeout(_stderr.chain(readLine), _SCHEDULE_TIMEOUT,
+      return timeout(_stderr.chain((stream) => readLine(stream)),
+          _SCHEDULE_TIMEOUT,
           "waiting for the next stderr line from process $name");
     });
   }
 
   /// Reads the remaining stdout from the process. This should only be called
   /// after kill() or shouldExit().
   Future<String> remainingStdout() {
     if (!_endScheduled) {
       throw new StateError("remainingStdout() should only be called after "
           "kill() or shouldExit().");
@@ skipping 218 matching lines @@
 /// calling [completion] is unnecessary.
 void expectLater(Future actual, matcher, {String reason,
     FailureHandler failureHandler, bool verbose: false}) {
   _schedule((_) {
     return actual.transform((value) {
       expect(value, matcher, reason: reason, failureHandler: failureHandler,
           verbose: false);
     });
   });
 }