Move browser tests that require installation into their own files.

test/runner/signal_test.dart

 // Copyright (c) 2015, 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.
 
 @TestOn("vm")
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 129 matching lines @@
     // Allow an event loop to pass so the preceding print can be handled.
     return new Future(() {
       // Loop forever so that if the test isn't stopped while running, it never
       // stops.
       while (true) {}
     });
   });
 }
 """);
 
-      return _startTest(["-p", "chrome", "test.dart"]).then((process) {
+      return _startTest(["-p", "content-shell", "test.dart"]).then((process) {
         return _lines.bind(process.stdout).skip(3).first.then((line) {
           expect(line, equals("running test"));
           process.kill();
           return process.exitCode;
         }).then((_) {
           expect(new Directory(_tempDir).listSync(), isEmpty);
         });
       });
     });
 
@@ skipping 107 matching lines @@
       });
     });
   });
 }
 
 Future<Process> _startTest(List<String> args) {
   new Directory(_tempDir).create();
   return startTest(args, workingDirectory: _sandbox,
       environment: {"_UNITTEST_TEMP_DIR": _tempDir});
 }