UI flow rework for device reset options. Reset made available from gaia screen. Tests adapted.

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="chromeos">. -->
 <grit-part>
   <message name="IDS_EMPTY_STRING" desc="Empty string, exist only to make code generic. No translation required.">
   </message>
   <message name="IDS_CHROMEBOOK" desc="The localized name for Chromebook.">
     Chromebook
   </message>
   <message name="IDS_CHROMEBOX" desc="The localized name for Chromebox">
@@ skipping 2672 matching lines @@
   <message name="IDS_EULA_TPM_BUSY" desc="Message bubble text">
     TPM is being prepared, please wait (this may take a few minutes)...
   </message>
   <message name="IDS_EULA_TPM_DISABLED" desc="Tooltip text describing why 'System security setting' link is disabled.">
     Trusted Platform Module (TPM) chip is disabled or absent.
   </message>
 
   <message name="IDS_RESET_SCREEN_WARNING_MSG" desc="Warning text shown on reset screen above the exclamation icon.">
     Reset this <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> device
   </message>
-  <message name="IDS_RESET_SCREEN_CONFIRMATION_WARNING_POWERWASH_MSG" desc="Warning text shown on confirmation-form of reset screen above the exclamation icon.">
+  <message name="IDS_RESET_SCREEN_WARNING_POWERWASH_MSG" desc="Warning text shown on confirmation-form of reset screen above the exclamation icon.">
     Powerwash your <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> device
   </message>
-  <message name="IDS_RESET_SCREEN_CONFIRMATION_WARNING_POWERWASH_AND_ROLLBACK_MSG" desc="Warning text shown on confirmation-form of reset screen above the exclamation icon.">
-    Powerwash your <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> device and revert to a previous update
+  <message name="IDS_RESET_SCREEN_WARNING_POWERWASH_AND_ROLLBACK_MSG" desc="Warning text shown on confirmation-form of reset screen above the exclamation icon.">
+    Powerwash your <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> device and return to the previous version
   </message>
   <message name="IDS_RESET_SCREEN_WARNING_DETAILS" desc="Warning text shown on reset screen below the exclamation icon.">
     Powerwash to reset your <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> device to be just like new.
   </message>
   <message name="IDS_RESET_SCREEN_CONFIRMATION_WARNING_DETAILS" desc="Warning text shown on confirmation-form of reset screen below the exclamation icon.">
     A Powerwash resets your <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> device to be just like new.
   </message>
   <message name="IDS_RESET_SCREEN_CONFIRMATION_WARNING_ROLLBACK_DETAILS" desc="Warning text shown on confirmation-form of reset screen below the exclamation icon.">
-    A Powerwash resets your <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> device to be just like new. Additionally, your device will revert to a previous update of <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph>.
+    A Powerwash resets your <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> device to be just like new. Your device will also be returned to the previously installed version of <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph>.
   </message>
   <message name="IDS_RESET_SCREEN_WARNING_DETAILS_DATA" desc="Additional warning text shown on reset screen below the main warning.">
     All user accounts and local data will be removed.
   </message>
   <message name="IDS_RESET_SCREEN_RESTART_MSG" desc="Text shown on reset screen below warning messages if device needs extra restart before powerwash.">
-    A restart is required before your device can be reset.
+    A restart is required to begin the Powerwash process. After restart you will be asked to confirm that you want to proceed.
   </message>
   <message name="IDS_RESET_SCREEN_ROLLBACK_OPTION" desc="Checkbox label for rollback option of powerwash process. Is shown on reset screen.">
-    Also revert to a previous <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> update.
+    Also return to the previously installed version of <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph>.
   </message>
   <message name="IDS_RESET_SCREEN_POWERWASH" desc="Powerwash button text">
     Powerwash
   </message>
+  <message name="IDS_RESET_SCREEN_POWERWASH_AND_REVERT" desc="Powerwash+rollback button text">
+    Powerwash and Revert
+  </message>
   <message name="IDS_RESET_SCREEN_RESET" desc="Reset button text. Button launches powerwash.">
     Reset
   </message>
   <message name="IDS_RESET_SCREEN_PREPARING_REVERT_PROMISE" desc="Message shown on reset screen after user initiates powerwash with version revert while revert is prepared until reboot.">
     <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> will restart and reset momentarily.
   </message>
   <message name="IDS_RESET_SCREEN_PREPARING_REVERT_SPINNER_MESSAGE" desc="Spinner message shown on reset screen after user initiates powerwash with version revert while revert is prepared until reboot.">
-    Reverting to previous <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> update.
+    Reverting to the previously installed version of <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph>
   </message>
   <message name="IDS_RESET_SCREEN_REVERT_ERROR" desc="Error message shown when revert was initiated but unavailable to be performed." meaning="Device reset screen revert option context.">
     Oops, something went wrong.
   </message>
   <message name="IDS_RESET_SCREEN_REVERT_ERROR_EXPLANATION" desc="Error description shown when revert was initiated but unavailable to be performed.">
-    <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> is unable to revert to the previous version. Please try Powerwash instead.
+    <ph name="IDS_SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph> is unable to revert to the previously installed version. Please try again to Powerwash your device.
   </message>
   <message name="IDS_RESET_SCREEN_REVERT_ERROR_BUTTON" desc="Reset device dialog, error page, revert error while initiating it, button title.">
     OK
   </message>
 
   <message name="IDS_WRONG_HWID_SCREEN_HEADER" desc="Header of message shown on screen notifying about malformed hardware ID.">
     A factory error has been detected
   </message>
   <message name="IDS_WRONG_HWID_SCREEN_MESSAGE_FIRST_PART" desc="Warning message shown on screen notifying about malformed hardware ID. First paragraph.">
     Unfortunately, your computer is configured with a malformed hardware ID. This prevents Chrome OS from updating with the latest security fixes and your computer <ph name="BEGIN_BOLD">$1</ph>may be vulnerable to malicious attacks<ph name="END_BOLD">$2</ph>.
@@ skipping 3069 matching lines @@
   <message name="IDS_SET_TIME_BUTTON_CLOSE" desc="Text for the button to close the window.">
     Done
   </message>
   <message name="IDS_SET_TIME_DATE_LABEL" desc="Label for the date input element.">
     System date
   </message>
   <message name="IDS_SET_TIME_TIME_LABEL" desc="Label for the time input element.">
     System time
   </message>
 </grit-part>