[Telemetry] Don't create a new Tab object at each navigation.

tools/telemetry/telemetry/core/extension_page.py

Index: tools/telemetry/telemetry/core/extension_page.py
diff --git a/tools/telemetry/telemetry/core/extension_page.py b/tools/telemetry/telemetry/core/extension_page.py
index 3402878b61102d809d3251b2f6b67506f6fe004e..d6c4087fa5e065580e1015a949ed1f68282d4557 100644
--- a/tools/telemetry/telemetry/core/extension_page.py
+++ b/tools/telemetry/telemetry/core/extension_page.py
@@ -1,21 +1,20 @@
 # 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 telemetry.core import web_contents
 
+
 class ExtensionPage(web_contents.WebContents):
-  """Represents a an extension page in the browser"""
+  """Represents an extension page in the browser"""
   def __init__(self, extension_id, url, inspector_backend):
     super(ExtensionPage, self).__init__(inspector_backend)
     self.extension_id = extension_id
     self.url = url
     assert url.startswith('chrome-extension://' + extension_id)
 
-  def __del__(self):
-    super(ExtensionPage, self).__del__()
-
   def Reload(self):
-    """ Reloading an extension page is used as a workaround for an extension
+    """Reloading an extension page is used as a workaround for an extension
     binding bug for old versions of Chrome (crbug.com/263162). After Navigate
     returns, we are guaranteed that the inspected page is in the correct state.
     """