[telemetry] Support absolute paths by changing file:/// to file://. More robust file path handling.

tools/perf/benchmarks/octane.py

 # 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.
 
 import os
 
 from telemetry import test
 from telemetry.core import util
 from telemetry.page import page_measurement
 from telemetry.page import page_set
@@ skipping 33 matching lines @@
 
 class Octane(test.Test):
   """Google's Octane JavaScript benchmark."""
   test = OctaneMeasurement
 
   def CreatePageSet(self, options):
     octane_dir = os.path.join(util.GetChromiumSrcDir(), 'chrome', 'test',
                               'data', 'perf', 'third_party', 'octane')
     return page_set.PageSet.FromDict({
         'pages': [
-          { 'url': 'file:///index.html?auto=1' }
+          { 'url': 'file://index.html?auto=1' }
           ]
         }, octane_dir)