Revert of Disable memory.long_running_idle_gmail_background_tbmv2 on Android

tools/perf/benchmarks/memory_infra.py

 # Copyright 2015 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.
 
 import re
 
 from core import perf_benchmark
 
 from telemetry import benchmark
 from telemetry.timeline import chrome_trace_category_filter
@@ skipping 213 matching lines @@
   @classmethod
   def Name(cls):
     return 'memory.long_running_idle_gmail_tbmv2'
 
   @classmethod
   def ShouldDisable(cls, possible_browser):
     return cls.IsSvelte(possible_browser)  # http://crbug.com/611167
 
 
 @benchmark.Enabled('has tabs')  # http://crbug.com/612210
-@benchmark.Disabled('android')  # http://crbug.com/648396
 class MemoryLongRunningIdleGmailBackground(_MemoryV8Benchmark):
   """Use (recorded) real world web sites and measure memory consumption
   of long running idle Gmail page """
   page_set = page_sets.LongRunningIdleGmailBackgroundPageSet
 
   @classmethod
   def Name(cls):
     return 'memory.long_running_idle_gmail_background_tbmv2'
 
   @classmethod
   def ShouldDisable(cls, possible_browser):  # http://crbug.com/616530
     return cls.IsSvelte(possible_browser)