Fix import order with isort tool.

tools/telemetry/telemetry/core/backends/browser_backend.py

 # Copyright 2013 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 import decorators
-
 from telemetry.core import web_contents
 from telemetry.core.forwarders import do_nothing_forwarder
 
 
 class ExtensionsNotSupportedException(Exception):
   pass
 
 
 class BrowserBackend(object):
   """A base class for browser backends."""
@@ skipping 73 matching lines @@
     raise NotImplementedError()
 
   def GetStandardOutput(self):
     raise NotImplementedError()
 
   def GetStackTrace(self):
     raise NotImplementedError()
 
   def GetSystemInfo(self):
     raise NotImplementedError()