[telemetry] Add a webdriver backend with support for IE.

tools/telemetry/telemetry/core/chrome/desktop_browser_finder.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.
 """Finds desktop browsers that can be controlled by telemetry."""
 
 import logging
 from operator import attrgetter
 import os
 import platform
 import subprocess
 import sys
 
 from telemetry.core import browser
 from telemetry.core import possible_browser
 from telemetry.core import profile_types
 from telemetry.core.chrome import cros_interface
 from telemetry.core.chrome import desktop_browser_backend
-from telemetry.core.platform import linux_platform_backend
-from telemetry.core.platform import mac_platform_backend
-from telemetry.core.platform import win_platform_backend
+from telemetry.core.platform import util as platform_util
 
 ALL_BROWSER_TYPES = ','.join([
     'exact',
     'release',
     'release_x64',
     'debug',
     'debug_x64',
     'canary',
     'content-shell-debug',
     'content-shell-release',
@@ skipping 13 matching lines @@
   def __repr__(self):
     return 'PossibleDesktopBrowser(browser_type=%s)' % self.browser_type
 
   # Constructs a browser.
   # Returns a touple of the form: (browser, backend)
   def _CreateBrowserInternal(self, delete_profile_dir_after_run):
     backend = desktop_browser_backend.DesktopBrowserBackend(
         self._options, self._local_executable, self._flash_path,
         self._is_content_shell,
         delete_profile_dir_after_run=delete_profile_dir_after_run)
-    if sys.platform.startswith('linux'):
-      p = linux_platform_backend.LinuxPlatformBackend()
-    elif sys.platform == 'darwin':
-      p = mac_platform_backend.MacPlatformBackend()
-    elif sys.platform == 'win32':
-      p = win_platform_backend.WinPlatformBackend()
-    else:
-      raise NotImplementedError()
-
-    b = browser.Browser(backend, p)
+    b = browser.Browser(backend,
+                        platform_util.CreatePlatformBackendForCurrentOS())
     backend.SetBrowser(b)
     return (b, backend)
 
   def Create(self):
     # If a dirty profile is needed, instantiate an initial browser object and
     # use that to create a dirty profile.
     creator_class = profile_types.GetProfileCreator(self.options.profile_type)
     if creator_class:
       logging.info(
           'Creating a dirty profile of type: %s', self.options.profile_type)
@@ skipping 169 matching lines @@
                     chromium_app_name, False):
         break
 
   if len(browsers) and not has_display:
     logging.warning(
       'Found (%s), but you do not have a DISPLAY environment set.' %
       ','.join([b.browser_type for b in browsers]))
     return []
 
   return browsers