Bug 1388627 - Remove obsolete Wait.until() calls from Window Manager Mixin. r=automatedtester

Given that both 'close' and 'close_chrome_window' wait for the underlying
tab or window to be closed, there is not need to explicitely wait in tests.

MozReview-Commit-ID: HOGgqzkNE9d

--HG--
extra : rebase_source : 0a1b197d499c9c2528e67e61172d90579f7ad696

testing/marionette/harness/marionette_harness/runner/mixins/window_manager.py

@@ -41,12 +41,6 @@ class WindowManagerMixin(object):
             self.marionette.switch_to_window(handle)
             self.marionette.close()
 
-            # Bug 1311350 - close() doesn't wait for tab to be closed.
-            Wait(self.marionette).until(
-                lambda mn: handle not in mn.window_handles,
-                message="Failed to close tab with handle {}".format(handle)
-            )
-
         self.marionette.switch_to_window(self.start_tab)
 
     def close_all_windows(self):
@@ -62,12 +56,6 @@ class WindowManagerMixin(object):
                 self.marionette.switch_to_window(handle)
                 self.marionette.close_chrome_window()
 
-                # Bug 1311350 - close_chrome_window() doesn't wait for window to be closed.
-                Wait(self.marionette).until(
-                    lambda mn: handle not in mn.chrome_window_handles,
-                    message="Failed to close window with handle {}".format(handle)
-                )
-
             self.marionette.switch_to_window(self.start_window)
 
     def open_tab(self, trigger="menu"):