Add tab.IsServiceWorkerReadyOrNotRegist() which tells whether serviceworker registration is finished

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 310fad75b324037e61609462dfb4a03748286eb8..bee55bce0c15bb9032b95fe0de91bb5dd130f737 100644
--- a/telemetry/telemetry/internal/browser/web_contents.py
+++ b/telemetry/telemetry/internal/browser/web_contents.py
@@ -10,6 +10,13 @@ from py_trace_event import trace_event
 
 DEFAULT_WEB_CONTENTS_TIMEOUT = 90
 
+class ServiceWorkerState(object):
+  # these strings should exactly match strings used in
+  # wait_for_serviceworker_registration.js

[falken, 2017/09/05 02:16:45]

Add some docu:

# The page did not call register().

+  NOT_REGISTERED = "not registered"

[falken, 2017/09/05 02:16:45]

# The page called register(), and there is not yet an active service worker.

+  INSTALLING = "installing"

[falken, 2017/09/05 02:16:45]

# The page called register(), and has an active service worker.

+  ACTIVATED = "activated"

[falken, 2017/09/05 02:16:45]

if you take up my suggestion, can change this to ACTIVE

+
 # TODO(achuith, dtu, nduca): Add unit tests specifically for WebContents,
 # independent of Tab.
 class WebContents(object):
@@ -30,6 +37,11 @@ class WebContents(object):
         'wait_for_frame.js')) as f:
       self._wait_for_frame_js = f.read()
 
+    with open(os.path.join(
+        os.path.dirname(__file__),
+        'wait_for_serviceworker_registration.js')) as f:
+      self._wait_for_serviceworker_js = f.read()
+
     # An incrementing ID used to query frame timing javascript. Using a new id
     # with each request ensures that previously timed-out wait for frame
     # requests don't impact new requests.
@@ -121,6 +133,43 @@ class WebContents(object):
         '{{ @script }}; window.__telemetry_testHasReachedNetworkQuiescence()',
         script=self._quiescence_js)
 
+  def QueryServiceWorkerState(self):
+    """Returns service worker registration state.
+
+    Returns:
+      ServiceWorkerState if service worker registration state is not unexpected.
+    Raises:
+      exceptions.EvaluateException
+      exceptions.Error: See EvaluateJavaScript() for a detailed list of
+      possible exceptions.
+    """
+    state = self.EvaluateJavaScript(
+        '{{ @script }}; window.__telemetry_queryServiceWorkerState()',
+        script=self._wait_for_serviceworker_js)
+    if state == 'not registered':
+      return ServiceWorkerState.NOT_REGISTERED
+    elif state == 'installing':
+      return ServiceWorkerState.INSTALLING
+    elif state == 'activated':
+      return ServiceWorkerState.ACTIVATED
+    else:
+      raise exceptions.EvaluateException(
+          "Unexpected service worker registration state.")

[falken, 2017/09/05 02:16:45]

maybe we can output 'state' as part of the exception

+
+  def IsServiceWorkerActivatedOrNotRegistered(self):

[falken, 2017/09/05 02:16:45]

IsServiceWorkerActiveOrNotRegistered

+    """Returns whether service worker is ready or not.
+
+    Returns:
+      True if the service worker registered from the page has reached to
+      ACTIVATED state. Also returns true if the page does not register service

[falken, 2017/09/05 02:16:45]

It's a bit nitty but we're not really checking that the service worker
registered from the page reached active. Suggest: "True if the page registered a
service worker and has an active service worker. Also returns true if...."

+      worker.
+    Raises:
+      exceptions.Error: See EvaluateJavaScript() for a detailed list of
+      possible exceptions.
+    """
+    return self.QueryServiceWorkerState() in {ServiceWorkerState.NOT_REGISTERED,
+                                              ServiceWorkerState.ACTIVATED}
+
   def ExecuteJavaScript(self, *args, **kwargs):
     """Executes a given JavaScript statement. Does not return the result.
 
@@ -229,7 +278,8 @@ class WebContents(object):
     if not script_to_evaluate_on_commit:
       script_to_evaluate_on_commit = ''
     script_to_evaluate_on_commit = (
-        self._quiescence_js + ';' + script_to_evaluate_on_commit)
+        self._quiescence_js + self._wait_for_serviceworker_js
+        + script_to_evaluate_on_commit)
     self._inspector_backend.Navigate(url, script_to_evaluate_on_commit, timeout)
 
   def IsAlive(self):