Fix "Reboot and reset" button behavior for rollback

For enterprise rollback, the "Reboot and reset" button should just
reboot the device. Without this, the button behavior is broken (nothing
happens when pressing it), because we don't generally allow powerwash
for managed devices. The admin-initiated rollback is an exception to it.

Bug: 868263
Change-Id: Iaa13429b35a52ef78d39e50ab42f17ac76a7eb33
Reviewed-on: https://chromium-review.googlesource.com/1152742
Commit-Queue: Marton Hunyady <hunyadym@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578832}

chrome/browser/resources/settings/about_page/about_page.js

@@ -472,7 +472,13 @@ Polymer({
 
   /** @private */
   onRelaunchAndPowerwashTap_: function() {
-    this.lifetimeBrowserProxy_.factoryReset(false);
+    if (this.currentUpdateStatusEvent_.rollback) {
+      // Wipe already initiated, simply relaunch.
+      this.lifetimeBrowserProxy_.relaunch();
+    } else {
+      this.lifetimeBrowserProxy_.factoryReset(
+          /* requestTpmFirmwareUpdate= */ false);
+    }
   },
 
   /**