Add key_idle_power_cases for ensuring idle activity on Android

tools/perf/page_sets/key_power_cases.py

+# Copyright 2015 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.
+from telemetry.page import page as page_module
+from telemetry.page import page_set as page_set_module
+
+
+class KeyPowerPage(page_module.Page):
+
+  def __init__(self, url, page_set, turn_screen_off):
+    super(KeyPowerPage, self).__init__(
+        url=url, page_set=page_set)
+    self.user_agent_type = 'mobile'
+    self._turn_screen_off = turn_screen_off
+
+  def RunNavigateSteps(self, action_runner):
+    action_runner._tab.browser.platform.android_action_runner.TurnScreenOn()
+    super(KeyPowerPage, self).RunNavigateSteps(action_runner)
+    action_runner.Wait(2)
+    if self._turn_screen_off:
+      action_runner._tab.browser.platform.android_action_runner.TurnScreenOff()
+      action_runner.Wait(2)
+
+  def RunPageInteractions(self, action_runner):
+    action_runner.Wait(20)
+    # TODO(jdduke): Restore screen state?
+

[rnephew (Reviews Here), 2015/04/23 18:28:05]

Should the turn screen off/on step be performed here, since its an 'interaction'
with the page instead of a navigation? Or does the measurements require it to
happen before it runs the interactions? Either way, I think it should restore
screen state before it goes on to the next page in the test. This current
implementation has it turning the screen back on as the first step in
RunNavigateSteps. 

[jdduke (slow), 2015/04/24 16:10:52]

Right, we don't want the "interaction" to include only the time where the screen
is actually off.

Unfortunately there doesn't appear to be a good way for a given page to perform
a cleanup step. I started down the path of adding such a method, but it got
messy rather quickly. This made me think perhaps the screen on/off logic should
be done at a higher level (e.g., by the measurement class), but that also gets a
bit messy.

The other question I had was about lockscreen state. We want to make sure Chrome
is in the foreground before we turn the screen off, so do we also need to make
sure the screen is both on AND unlocked? How does our current power tests handle
this? Do we explicitly unlock the screen and turn it on? Or are those done with
the screen off (in which case I wonder if this is impacting how faithful the
power interaction metrics are).

+
+class KeyPowerCasesPageSet(page_set_module.PageSet):
+
+  """ Key power cases """
+
+  def __init__(self):
+    super(KeyPowerCasesPageSet, self).__init__(
+      user_agent_type='mobile')
+
+    foreground_urls_list = [
+      # Why: Ensure minimal activity for static, empty pages in the foreground.
+      'file://key_power_cases/blank.html',

[rnephew (Reviews Here), 2015/04/23 18:28:05]

I dont know enough about telemetry to know if it should use local files or not.
I know it typically uses WPR.

[jdduke (slow), 2015/04/24 16:10:52]

Typically, yes, but these are (intentionally) synthetic examples. Other pagesets
also rely on local files, e.g., key_silk_cases.

+    ]
+
+    for url in foreground_urls_list:
+      self.AddUserStory(KeyPowerPage(url, self, False))
+
+    background_urls_list = [
+      # Why: Ensure animated GIFs aren't processed when Chrome is backgrounded.
+      'file://key_power_cases/animated-gif.html',
+      # Why: Ensure CSS animations aren't processed when Chrome is backgrounded.
+      'file://key_power_cases/css-animation.html',
+      # Why: Ensure rAF is suppressed when Chrome is backgrounded.
+      'file://key_power_cases/request-animation-frame.html',
+      # Why: Ensure setTimeout is throttled when Chrome is backgrounded.
+      'file://key_power_cases/set-timeout.html',
+    ]
+
+    for url in background_urls_list:
+      self.AddUserStory(KeyPowerPage(url, self, True))