Show a label to describe some invalid drag-drop operations in Files app.

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 729 matching lines @@
   </message>
   <message name="IDS_FILE_BROWSER_SUGGEST_DIALOG_FOR_PROVIDERS_TITLE" desc="Title of the suggest app dialog, which shows the list of the apps that can be added to the left nav of Files app.">
     Available services
   </message>
   <message name="IDS_FILE_BROWSER_SUGGEST_DIALOG_LINK_TO_WEBSTORE" desc="Text of the link to the app list on Chrome Webstore, which shows the more apps than in the suggest app dialog.">
     See more...
   </message>
   <message name="IDS_FILE_BROWSER_SUGGEST_DIALOG_INSTALLATION_FAILED" desc="Error message when the installation of the app from WebStore is failed.">
     Installation failed.
   </message>
+  <message name="IDS_FILE_BROWSER_DROP_TARGET_DEVICE_WRITE_PROTECTED" desc="Tooltip label displayed besides mouse pointer while dragging files or folders over a write-protected folder or disk.">
+    Device is read-only
+  </message>
+  <message name="IDS_FILE_BROWSER_DROP_TARGET_ACCESS_RESTRICTED" desc="Tooltip label displayed besides mouse pointer when dragging files or folders over a removable device whose write access is restricted by administration policy.">
+    Access restricted
+  </message>
 
   <message name="IDS_FILE_BROWSER_SELECT_FOLDER_TITLE" desc="Select folder title.">
     Select a folder to open
   </message>
   <message name="IDS_FILE_BROWSER_SELECT_UPLOAD_FOLDER_TITLE" desc="Select folder title for upload.">
     Select a folder to upload
   </message>
   <message name="IDS_FILE_BROWSER_SELECT_OPEN_FILE_TITLE" desc="Select open file title.">
     Select a file to open
   </message>
@@ skipping 5809 matching lines @@
   <message name="IDS_PRINT_JOB_NOTIFICATION_PAUSE_BUTTON" desc="Text on the button for the user to pause the current print job.">
     Pause printing
   </message>
   <message name="IDS_PRINT_JOB_NOTIFICATION_RESUME_BUTTON" desc="Text on the button for the user to resume the current print job.">
     Resume printing
   </message>
   <message name="IDS_PRINT_JOB_NOTIFICATION_GET_HELP_BUTTON" desc="Text on the button for the user to get help about the current print job.">
     Get help
   </message>
 </grit-part>