[Telemetry] Move from telemetry WaitFor to py_utils WaitFor

telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py

Index: telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py
diff --git a/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py b/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py
index 05c425c28fb5fd088496ba558c2262d216543e54..1a44dd5bef04778c6aff857eda2b1cefdfc4a585 100644
--- a/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py
+++ b/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py
@@ -8,7 +8,6 @@ import shlex
 import sys
 
 from telemetry.core import exceptions
-from telemetry.core import util
 from telemetry import decorators
 from telemetry.internal.backends import browser_backend
 from telemetry.internal.backends.chrome import extension_backend
@@ -19,6 +18,8 @@ from telemetry.internal.browser import user_agent
 from telemetry.internal.browser import web_contents
 from telemetry.testing import options_for_unittests
 
+import py_utils
+
 
 class ChromeBrowserBackend(browser_backend.BrowserBackend):
   """An abstract class for chrome browser backends. Provides basic functionality
@@ -154,8 +155,8 @@ class ChromeBrowserBackend(browser_backend.BrowserBackend):
     """ Wait for browser to come up. """
     try:
       timeout = self.browser_options.browser_startup_timeout
-      util.WaitFor(self.HasBrowserFinishedLaunching, timeout=timeout)
-    except (exceptions.TimeoutException, exceptions.ProcessGoneException) as e:
+      py_utils.WaitFor(self.HasBrowserFinishedLaunching, timeout=timeout)
+    except (py_utils.TimeoutException, exceptions.ProcessGoneException) as e:
       if not self.IsBrowserRunning():
         raise exceptions.BrowserGoneException(self.browser, e)
       raise exceptions.BrowserConnectionGoneException(self.browser, e)
@@ -169,8 +170,8 @@ class ChromeBrowserBackend(browser_backend.BrowserBackend):
     assert self._devtools_client, (
         'Waiting for extensions required devtool client to be initiated first')
     try:
-      util.WaitFor(self._AllExtensionsLoaded, timeout=60)
-    except exceptions.TimeoutException:
+      py_utils.WaitFor(self._AllExtensionsLoaded, timeout=60)
+    except py_utils.TimeoutException:
       logging.error('ExtensionsToLoad: ' +
           repr([e.extension_id for e in self._extensions_to_load]))
       logging.error('Extension list: ' +