MD Settings: About page, implementing channel switcher dialog.

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- About Page -->
   <if expr="chromeos">
     <message name="IDS_SETTINGS_ABOUT_PAGE_CHECK_FOR_UPDATES" desc="The button label to check for updates and apply (download and install) if found">
       Check for updates
     </message>
     <message name="IDS_SETTINGS_ABOUT_PAGE_CURRENT_CHANNEL_STABLE" desc="The stable label in the message about current channel.">
       stable
@@ skipping 21 matching lines @@
     </message>
     <message name="IDS_SETTINGS_UPGRADE_UPDATING_CHANNEL_SWITCH" desc="Status label: Updating ChromiumOS/ChromeOS to a specified channel">
       Updating your device to <ph name="CHANNEL_NAME">$1<ex>stable</ex></ph> channel
     </message>
     <message name="IDS_SETTINGS_UPGRADE_SUCCESSFUL_CHANNEL_SWITCH" desc="Status label: Channel was successfully switched on ChromiumOS/ChromeOS">
       Channel changed. Restart your device to apply changes.
     </message>
     <message name="IDS_SETTINGS_UPGRADE_UP_TO_DATE" desc="Status label: Already up to date (ChromiumOS/ChromeOS)">
       Your <ph name="DEVICE_TYPE">$1<ex>Chromebook</ex></ph> is up to date.
     </message>
+
+    <!-- About Page: Channel switcher dialog -->
+    <message name="IDS_SETTINGS_ABOUT_PAGE_CHANGE_CHANNEL" desc="The label for the button for channel switch.">
+      Change channel
+    </message>
+    <message name="IDS_SETTINGS_ABOUT_PAGE_CHANGE_CHANNEL_AND_POWERWASH" desc="The label for the button for channel switch and powerwash.">

[dschuyler, 2016/05/26 01:35:49]

optional:
Several of these descriptions could be 
less 'wordy'. E.g. instead of the above:
"Button label for channel switch and powerwash."

[dpapad, 2016/05/26 17:58:55]

Done. I had simply copied all the descriptions from the old Options existing
strings.

+      Change channel and Powerwash
+    </message>
+    <message name="IDS_SETTINGS_ABOUT_PAGE_DELAYED_WARNING_MESSAGE" desc="Message that notifies user that channel change will be applied later.">
+      You are changing to a channel with an older version of <ph name="PRODUCT_NAME">$1<ex>Chrome OS</ex></ph>. The channel change will be applied when the channel version matches the version currently installed on your device.
+    </message>
+    <message name="IDS_SETTINGS_ABOUT_PAGE_DELAYED_WARNING_TITLE" desc="The title for the message that notifies user that channel change will be applied later.">

[dschuyler, 2016/05/26 01:35:49]

optional:
"Title for the message that the channel change will be applied later."

[dpapad, 2016/05/26 17:58:55]

Done.

+      Channel change will be applied later.
+    </message>
+    <message name="IDS_SETTINGS_ABOUT_PAGE_POWERWASH_WARNING_MESSAGE" desc="Message that warns user about powerwash.">
+      This will remove all local users, files, data, and other settings after your next restart. All users will need to sign in again.
+    </message>
+    <message name="IDS_SETTINGS_ABOUT_PAGE_POWERWASH_WARNING_TITLE" desc="The title for the message that warns user about powerwash.">
+      Powerwash required on next reboot
+    </message>
+    <message name="IDS_SETTINGS_ABOUT_PAGE_UNSTABLE_WARNING_TITLE" desc="The title for the message that warns user about switching to developer (unstable) channel.">
+      Warning: you are switching to developer channel
+    </message>
+    <message name="IDS_SETTINGS_ABOUT_PAGE_UNSTABLE_WARNING_MESSAGE" desc="Message that warns user about switching to developer (unstable) channel.">

[dschuyler, 2016/05/26 01:35:50]

optional:
"Warning about switching to developer (unstable) channel."

[dpapad, 2016/05/26 17:58:55]

Done.

+      You are updating to an unstable version of <ph name="PRODUCT_NAME">$1<ex>Chrome OS</ex></ph> which contains features that are in progress. Crashes and unexpected bugs will occur. Please proceed with caution.
+    </message>
   </if>
   <if expr="not chromeos">
     <message name="IDS_SETTINGS_ABOUT_PAGE_RELAUNCH" desc="The label for the relaunch button that relaunches the browser once update is complete">
       Relaunch
     </message>
   </if>
   <if expr="_google_chrome">
     <message name="IDS_SETTINGS_ABOUT_PAGE_REPORT_AN_ISSUE" desc="Text of the button which allows the user to report an issue with Chrome.">
       Report an issue
     </message>
@@ skipping 1319 matching lines @@
       System
     </message>
     <message name="IDS_SETTINGS_SYSTEM_HARDWARE_ACCELERATION_LABEL" desc="Label for the checkbox that forces Chrome to render via hardware acceleration (GPU) when available.">
       Use hardware acceleration when available
     </message>
     <message name="IDS_SETTINGS_SYSTEM_PROXY_SETTINGS_BUTTON" desc="Text for the button that changes a user's network proxy settings.">
       Change proxy settings
     </message>
   </if>
 </grit-part>