chromeos: Add Power device page to chrome://md-settings.

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- Main Page -->
   <if expr="chromeos">
     <message name="IDS_SETTINGS_SECONDARY_USER_BANNER" desc="Banner displayed in settings page when the user is secondary in a multi-profile session.">
       Some settings belonging to <ph name="PRIMARY_EMAIL">$1<ex>john@google.com</ex></ph> are being shared with you. These settings only affect your account when using multiple sign-in.
     </message>
   </if>
 
@@ skipping 2863 matching lines @@
       Delete offline files?
     </message>
     <message name="IDS_SETTINGS_STORAGE_CLEAR_DRIVE_CACHE_DESCRIPTION" desc="Description in the storage manager confirmation dialog to remove Google Drive offline files.">
       Temporary Google Drive offline files will be deleted. Files that you’ve set as available offline won’t be deleted from this device.
     </message>
     <message name="IDS_SETTINGS_STORAGE_DELETE_ALL_BUTTON_TITLE" desc="In storage manager confirmation dialog, label for the button to delete offline files.">
       Delete files
     </message>
 
     <!-- Power -->
-    <message name="IDS_SETTINGS_POWER_SOURCE_LABEL" desc="The label for the power source dropdown in the Power overlay.">
+    <message name="IDS_SETTINGS_POWER_TITLE" desc="In Device Settings, the title for power management.">
+      Power
+    </message>
+    <message name="IDS_SETTINGS_POWER_SOURCE_LABEL" desc="In Device Settings > Power, the label for the power source dropdown.">
       Power source
     </message>
-    <message name="IDS_SETTINGS_POWER_SOURCE_BATTERY" desc="The text referring to the battery as the power source.">
+    <message name="IDS_SETTINGS_POWER_SOURCE_BATTERY" desc="In Device Settings > Power, the text referring to the battery as the power source.">
       Battery
     </message>
-    <message name="IDS_SETTINGS_POWER_SOURCE_AC_ADAPTER" desc="The text referring to a dedicated charger like an AC adapter as the power source.">
+    <message name="IDS_SETTINGS_POWER_SOURCE_AC_ADAPTER" desc="In Device Settings > Power, the text referring to a dedicated charger like an AC adapter as the power source.">
       AC adapter
     </message>
-    <message name="IDS_SETTINGS_POWER_SOURCE_LOW_POWER_CHARGER" desc="The text referring to a low-power charger like a USB charger as the power source.">
+    <message name="IDS_SETTINGS_POWER_SOURCE_LOW_POWER_CHARGER" desc="In Device Settings > Power, the text referring to a low-power charger like a USB charger as the power source.">
       Low-power charger
     </message>
-    <message name="IDS_SETTINGS_POWER_SOURCE_CALCULATING" desc="The description in the 'Power' overlay when the power status is being determined.">
+    <message name="IDS_SETTINGS_POWER_SOURCE_CALCULATING" desc="In Device Settings > Power, the power source description when the power status is being determined.">
       Checking...
     </message>
   </if>
 
   <!-- System Page -->
   <if expr="not chromeos">
     <message name="IDS_SETTINGS_SYSTEM" desc="Title of the system settings.">
       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>