[Telemetry] Move from telemetry WaitFor to py_utils WaitFor

telemetry/telemetry/internal/backends/chrome/ios_browser_backend.py

Index: telemetry/telemetry/internal/backends/chrome/ios_browser_backend.py
diff --git a/telemetry/telemetry/internal/backends/chrome/ios_browser_backend.py b/telemetry/telemetry/internal/backends/chrome/ios_browser_backend.py
index c2508fa4802533d83ea63eaf41e7c256037f171e..fac37cb2e7fab7568f9a413f0ce583feef1fa333 100644
--- a/telemetry/telemetry/internal/backends/chrome/ios_browser_backend.py
+++ b/telemetry/telemetry/internal/backends/chrome/ios_browser_backend.py
@@ -8,11 +8,11 @@ import logging
 import re
 import urllib2
 
-from telemetry.core import exceptions
-from telemetry.core import util
 from telemetry.internal.backends.chrome import chrome_browser_backend
 from telemetry.internal.backends.chrome import system_info_backend
 
+import py_utils
+
 
 class IosBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
   _DEBUGGER_URL_BUILDER = 'ws://localhost:%i/devtools/page/%i'
@@ -89,8 +89,8 @@ class IosBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
       try:
         # Retry a few times since it can take a few seconds for this API to be
         # ready, if ios_webkit_debug_proxy is just launched.
-        data = util.WaitFor(GetData, 5)
-      except exceptions.TimeoutException as e:
+        data = py_utils.WaitFor(GetData, 5)
+      except py_utils.TimeoutException as e:
         logging.debug('Timeout retrieving data from iOS device')
         logging.debug(e)
         return []