[telemetry] Move tab from RunState to PageState.

tools/perf/measurements/memory.py

 # Copyright (c) 2012 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.
 
 from metrics import memory
 from telemetry.page import page_measurement
 
 class Memory(page_measurement.PageMeasurement):
   def __init__(self):
     super(Memory, self).__init__('stress_memory')
@@ skipping 23 matching lines @@
       # intervals (~20 secs).
       # This is a minor optimization to ensure it'll dump the last file when
       # the test completes.
       tab.ExecuteJavaScript("""
         if (chrome && chrome.memoryBenchmarking) {
           chrome.memoryBenchmarking.heapProfilerDump('renderer', 'final');
           chrome.memoryBenchmarking.heapProfilerDump('browser', 'final');
         }
       """)
 
-  def DidRunTest(self, tab, results):
+  def DidRunTest(self, browser, results):
     self._memory_metric.AddSummaryResults(results)