[Telemetry] Add web_contents.WaitForJavaScriptCondition method

telemetry/telemetry/internal/browser/web_contents.py

Index: telemetry/telemetry/internal/browser/web_contents.py
diff --git a/telemetry/telemetry/internal/browser/web_contents.py b/telemetry/telemetry/internal/browser/web_contents.py
index 12e7b171df4f688b50a80d2d3356510e70654a9a..ef0017c9f41681eef632514d3b61c76c7b44bcb6 100644
--- a/telemetry/telemetry/internal/browser/web_contents.py
+++ b/telemetry/telemetry/internal/browser/web_contents.py
@@ -174,6 +174,16 @@ class WebContents(object):
     """
     return self._inspector_backend.EvaluateJavaScript2(*args, **kwargs)
 
+  def WaitForJavaScriptCondition(self, expr, timeout=None):
+    """Method made available to ease the migration of ChromeOS clients.
+
+    Chromium/catapult clients should use WaitForJavaScriptCondition2
+    until the process of migration is over.
+
+    See: crbug.com/682812, catapult:#3028.
+    """
+    self._inspector_backend.WaitForJavaScriptCondition2(expr, timeout=timeout)
+
   def WaitForJavaScriptCondition2(self, *args, **kwargs):
     """Wait for a JavaScript condition to become true.