Change chrome://settings strings for ARC OptIn.

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>
   <!-- Idle logout dialog for retail mode -->
   <message name="IDS_IDLE_LOGOUT_TITLE" desc="Dialog title for the idle logout dialog. Used in retail mode only.">
     Are you still there?
   </message>
@@ skipping 6803 matching lines @@
     Installing
   </message>
   <message name="IDS_FLAGS_PRINTER_PROVIDER_SEARCH_APP_NAME" desc="Name of the flag used to enable launching Chrome Web Store Gallery widget app for searching for printer provider apps.">
     Chrome Web Store Gallery app for printer drivers
   </message>
   <message name="IDS_FLAGS_PRINTER_PROVIDER_SEARCH_APP_DESCRIPTION" desc="Description of a flag in chrome://flags that enables launching Chrome Web Store Gallery widget app for searching for printer provider apps.">
     Enables Chrome Web Store Gallery app for printer drivers. The app searches Chrome Web Store for extensions that support printing to a USB printer with specific USB ID.
   </message>
 
   <!-- Android Apps -->
   <message name="IDS_OPTIONS_ARC_TITLE" desc="The title of Android Apps section.">

[elijahtaylor1, 2016/08/11 16:55:04]

probably worth changing the translation messages as well, unless we've been told
not to

[Josh Horwich, 2016/08/11 17:04:27]

Done.

-    Android apps
+    Google Play Store
   </message>
   <message name="IDS_OPTIONS_ARC_ENABLE" desc="Label for the checkbox that enables Android apps.">
-    Enable Android apps on your Chromebook.
+    Enable Google Play Store on your Chromebook.
   </message>
   <message name="IDS_OPTIONS_ARC_MANAGE_APPS" desc="Label for launching  Android apps settings.">
-    Manage your Android apps in <ph name="BEGIN_LINK">&lt;a is="action-link" id="android-apps-settings-link" role="link"&gt;</ph>Settings<ph name="END_LINK">&lt;/a&gt;</ph>.
+    Manage your Android <ph name="BEGIN_LINK">&lt;a is="action-link" id="android-apps-settings-link" role="link"&gt;</ph>preferences<ph name="END_LINK">&lt;/a&gt;</ph>.
   </message>
   <message name="IDS_ARC_NOTIFICATION_TITLE" desc="Title of the first-run notification that enables Android apps.">
     Google Play Store
   </message>
   <message name="IDS_ARC_NOTIFICATION_MESSAGE" desc="Description message of the first-run notification that enables Android apps.">
     Over a million apps and games now available on your <ph name="DEVICE_TYPE">$1<ex>Chromebook</ex></ph>.
   </message>
   <message name="IDS_ARC_OPEN_PLAY_STORE_NOTIFICATION_BUTTON" desc="Label for the button in the first-run notification that enables Android apps.">
     Open Play Store
   </message>
@@ skipping 115 matching lines @@
   <message name="IDS_CRITICALLY_LOW_DISK_NOTIFICATION_TITLE" desc="Title of the notification warning users that they are critically low on disk space.">
     Device disk space critically low
   </message>
   <message name="IDS_CRITICALLY_LOW_DISK_NOTIFICATION_MESSAGE" desc="Notification text warning users that they are critically low on disk space.">
     Free up disk space or device will become unresponsive.
   </message>
   <message name="IDS_LOW_DISK_NOTIFICATION_BUTTON" desc="Button on the low disk notification to open storage management.">
     Manage storage
   </message>
 </grit-part>