Telemetry media_measurement plus play action and tests.

tools/telemetry/telemetry/page/actions/play.py

Index: tools/telemetry/telemetry/page/actions/play.py
diff --git a/tools/telemetry/telemetry/page/actions/play.py b/tools/telemetry/telemetry/page/actions/play.py
new file mode 100644
index 0000000000000000000000000000000000000000..0234db200a42e311800f426c6f20dda66ae6e415
--- /dev/null
+++ b/tools/telemetry/telemetry/page/actions/play.py
@@ -0,0 +1,60 @@
+# 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 "play" action on media elements.
+
+Media elements can be specified by a selector attribute. If no selector is
+defined then then the action attempts to play the first video element or audio
+element on the page. A selector can also be 'all' to play all media elements.
+
+Other attributes to use are: wait_for_playing and wait_for_ended, which forces
+the action to wait untill playing and ended events get fired respectively.
+"""
+
+import os
+
+from telemetry.core import exceptions
+from telemetry.core import util
+from telemetry.page.actions import page_action
+
+
+class PlayAction(page_action.PageAction):
+  def __init__(self, attributes=None):
+    super(PlayAction, self).__init__(attributes)
+
+  def WillRunAction(self, page, tab):
+    """Load the media metrics JS code prior to running the action."""
+    deps_found = tab.EvaluateJavaScript('window.__mediaRecorders != undefined')
+    if not deps_found:
+      with open(

[nduca, 2013/06/17 23:01:33]

you should have play.js here --- you cant share code between these two js files
im afraid... its just different layers of the cake, sorry!

[shadi, 2013/06/18 00:30:01]

But it is the same code that we want to run. What is wrong with using it this
way?

We can not inject the same code twice...The measurement class needs it in case
we are not running any actions, and actions need it in case they are run outside
the media_measurement scope.

+          # TODO(shadi): Find or define a global path to src/tools in Telemetry.
+          os.path.join(os.path.dirname(__file__), '..', '..', '..', '..',
+                       'perf', 'perf_tools', 'media_metrics.js')) as f:
+        js = f.read()
+        tab.ExecuteJavaScript(js)
+
+  def RunAction(self, page, tab, previous_action):
+    try:
+      selector = self.selector if hasattr(self, 'selector') else ''
+      tab.ExecuteJavaScript('window.__playMedia(\'%s\');' % selector)
+      # Check if we need to wait for 'playing' event to fire.
+      if hasattr(self, 'wait_for_playing') and self.wait_for_playing:
+        self.WaitForEvent(tab, selector, 'playing')
+      # Check if we need to wait for 'ended' event to fire.
+      if hasattr(self, 'wait_for_ended') and self.wait_for_ended:
+        self.WaitForEvent(tab, selector, 'ended')
+    except exceptions.EvaluateException:
+      raise page_action.PageActionFailed('Cannot play media element(s) with '
+                                         'selector = %s.' % selector)
+
+  def WaitForEvent(self, tab, selector, event_name):
+    """Halts play action until the selector's event is fired."""
+    # TODO(shadi): add action attribute to control timeout for videos that take
+    # longer than 60 secs to end.
+    util.WaitFor(lambda: self.HasEventCompleted(tab, selector, event_name),
+                 timeout=60, poll_interval=0.5)
+
+  def HasEventCompleted(self, tab, selector, event_name):
+    return tab.EvaluateJavaScript(
+        'window.__hasEventCompleted(\'%s\', \'%s\');' % (selector, event_name))