Change WebView Perf builder after lab move

masters/master.chromium.perf.fyi/slaves.cfg

 # -*- python -*-
 # ex: set syntax=python:
 
 # 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.
 
 # See master.experimental/slaves.cfg for documentation.
 
 slaves = [
@@ skipping 24 matching lines @@
   {
     'master': 'ChromiumPerfFyi',
     'hostname': 'build19-a1',
     'builder': 'android_nexus5_oilpan_perf',
     'os': 'linux',
     'version': 'precise',
     'bits': '64',
   },
   {
     'master': 'ChromiumPerfFyi',
-    'hostname': 'build15-a1',
+    'hostname': 'build58-b1',
     'builder': 'android_webview_aosp_perf',
     'os': 'linux',
     'version': 'precise',
     'bits': '64',
   },
   {
     'master': 'ChromiumPerfFyi',
     'hostname': 'build131-a1',
     'builder': 'Win 7 Intel GPU Perf (Xeon)',
     'os': 'win',
@@ skipping 66 matching lines @@
   },
   {
     'master': 'ChromiumPerfFyi',
     'hostname': 'slave50-c1',
     'builder': 'Linux CT Top1K RR Perf',
     'os': 'linux',
     'version': 'trusty',
     'bits': '64',
   },
 ]