Fix jetstream unreferenced tab variable.

tools/perf/benchmarks/jetstream.py

 # Copyright 2014 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.
 
 """Runs Apple's JetStream benchmark.
 
 JetStream combines a variety of JavaScript benchmarks, covering a variety of
 advanced workloads and programming techniques, and reports a single score that
 balances them using geometric mean.
 
@@ skipping 28 matching lines @@
     page.script_to_evaluate_on_commit = """
         var __results = [];
         var __real_log = window.console.log;
         window.console.log = function() {
           __results.push(Array.prototype.join.call(arguments, ' '));
           __real_log.apply(this, arguments);
         }
         """
 
   def ValidateAndMeasurePage(self, page, tab, results):
-    del page, tab  # unused
+    del page  # unused
     get_results_js = """
         (function() {
           for (var i = 0; i < __results.length; i++) {
             if (!__results[i].indexOf('Raw results: ')) return __results[i];
           }
           return null;
         })();
         """
 
     tab.WaitForDocumentReadyStateToBeComplete()
@@ skipping 30 matching lines @@
 
   def CreateStorySet(self, options):
     ps = story.StorySet(
         archive_data_file='../page_sets/data/jetstream.json',
         base_dir=os.path.dirname(os.path.abspath(__file__)),
         cloud_storage_bucket=story.INTERNAL_BUCKET)
     ps.AddStory(page_module.Page(
         'http://browserbench.org/JetStream/', ps, ps.base_dir,
         make_javascript_deterministic=False))
     return ps