Telemetry media Seek action and metrics.

tools/telemetry/telemetry/page/actions/seek.py

+# Copyright (c) 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""A Telemetry page_action that performs the "seek" action on media elements.
+
+Action attributes are:
+- seek_time: The media time to seek to. Test fails if not provided.
+- selector: If no selector is defined then the action attempts to seek the first
+            media element on the page. If 'all' then seek all media elements.
+- log_seek_time: If true the seek time is recorded, otherwise media measurement
+                 will not be aware of the seek action. Used to perform multiple
+                 seeks. Default true.
+- wait_for_seeked: If true forces the action to wait for seeked event to fire.
+                   Default false.
+- wait_timeout: Timeout to wait for seeked event. Only valid with
+                wait_for_seeked=true
+"""
+
+import os
+
+from telemetry.core import exceptions
+from telemetry.core import util
+from telemetry.page.actions import page_action
+
+
+class SeekAction(page_action.PageAction):
+  def __init__(self, attributes=None):
+    super(SeekAction, self).__init__(attributes)
+
+  def WillRunAction(self, page, tab):
+    """Load the media metrics JS code prior to running the action."""
+    with open(os.path.join(os.path.dirname(__file__), 'seek.js')) as f:
+      js = f.read()
+      tab.ExecuteJavaScript(js)
+
+  def RunAction(self, page, tab, previous_action):
+    try:
+      if not hasattr(self, 'seek_time'):

[dtu, 2013/07/20 01:20:56]

assert this instead of raising PageActionFailed.

[shadi, 2013/07/22 19:18:31]

Done.

+        raise page_action.PageActionFailed('Seek time is missing in the action')
+      selector = self.selector if hasattr(self, 'selector') else ''
+      log_seek = self.log_seek if hasattr(self, 'log_seek') else True
+      tab.ExecuteJavaScript('window.__seekMedia(\'%s\', \'%s\', \'%s\');' %

[dtu, 2013/07/20 01:20:56]

" in place of \'

[shadi, 2013/07/22 19:18:31]

Done.

+                            (selector, self.seek_time, log_seek))
+      timeout = self.wait_timeout if hasattr(self, 'wait_timeout') else 60
+      # Check if we need to wait for 'seeked' event to fire.
+      if hasattr(self, 'wait_for_seeked') and self.wait_for_seeked:
+        self.WaitForEvent(tab, selector, 'seeked', timeout)
+    except exceptions.EvaluateException:
+      raise page_action.PageActionFailed('Cannot seek media element(s) with '
+                                         'selector = %s.' % selector)
+
+  def WaitForEvent(self, tab, selector, event_name, timeout):
+    """Halts seek action until the selector's event is fired."""
+    util.WaitFor(lambda: self.HasEventCompleted(tab, selector, event_name),
+                 timeout=timeout, poll_interval=0.5)
+
+  def HasEventCompleted(self, tab, selector, event_name):
+    return tab.EvaluateJavaScript(
+        'window.__hasEventCompleted(\'%s\', \'%s\');' % (selector, event_name))