[Telemetry] Fix blink_perf output trace names on Windows.

tools/perf/perf_tools/blink_perf.py

 # Copyright (c) 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.
 
 """This measurement runs a blink performance test and reports the results."""
 
 import os
 import sys
 
 from telemetry.core import util
@@ skipping 19 matching lines @@
       sys.exit(1)
 
     page_set_dict = {'pages': []}
 
     def _AddPage(path):
       if not path.endswith('.html'):
         return
       if '../' in open(path, 'r').read():
         # If the page looks like it references its parent dir, include it.
         page_set_dict['serving_dirs'] = [os.path.dirname(os.path.dirname(path))]
-      page_set_dict['pages'].append({'url': 'file://' + path})
+      page_set_dict['pages'].append({'url':
+                                     'file://' + path.replace('\\', '/')})
 
     def _AddDir(dir_path, skipped):
       for path in os.listdir(dir_path):
         if path == 'resources':
           continue
         path = os.path.join(dir_path, path)
         if path.startswith(tuple([os.path.join(page_set_arg, s)
                                   for s in skipped])):
           continue
         if os.path.isdir(path):
@@ skipping 35 matching lines @@
       if not line.startswith('values '):
         continue
       parts = line.split()
       values = [float(v.replace(',', '')) for v in parts[1:-1]]
       units = parts[-1]
       metric = page.display_url.split('.')[0].replace('/', '_')
       results.Add(metric, units, values)
       break
 
     print log