[Autotest] New test for policy_WilcoUSBPowershare.

Testing the effects of the DeviceUsbPowerShareEnabled policy.

BUG=None
TEST=this

Change-Id: Ib3702f2a61ff8d23691f00d5653a8af2fbcdf532
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/1832308
Tested-by: Ruben Zakarian <rzakarian@chromium.org>
Reviewed-by: Nick Crews <ncrews@chromium.org>
Reviewed-by: Derek Beckett <dbeckett@chromium.org>
Reviewed-by: Fei Ling <feiling@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
diff --git a/server/cros/servo/servo.py b/server/cros/servo/servo.py
index 134e389..71f0ae9 100644
--- a/server/cros/servo/servo.py
+++ b/server/cros/servo/servo.py
@@ -435,6 +435,14 @@
         self.set_nocheck('power_key', press_secs)
 
 
+    def pwr_button(self, action='press'):
+        """Simulate a power button press.
+
+        @param action: str; could be press or could be release.
+        """
+        self.set_nocheck('pwr_button', action)
+
+
     def lid_open(self):
         """Simulate opening the lid and raise exception if all attempts fail"""
         self.set('lid_open', 'yes')
@@ -448,6 +456,12 @@
         self.set('lid_open', 'no')
         time.sleep(Servo.SLEEP_DELAY)
 
+
+    def vbus_power_get(self):
+        """Get current vbus_power."""
+        return self.get('vbus_power')
+
+
     def volume_up(self, timeout=300):
         """Simulate pushing the volume down button.