Move sandboxed_unpacker.{h,cc} from chrome/ to extensions/

extensions/extensions_strings.grd

 <?xml version="1.0" encoding="utf-8"?>
 
 <!--
   Strings for the extensions module. Used mostly for low-level error messages.
   Where possible new strings should be kept in Chrome and the extensions module
   should return an error code, message flag, etc.
 -->
 
 <grit latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
@@ skipping 422 matching lines @@
       <message name="IDS_EXTENSION_WARNING_RELOAD_TOO_FREQUENT" desc="Warning message which indates that an extension got stuck in a reload loop.">
         This extension reloaded itself too frequently.
       </message>
       <message name="IDS_EXTENSION_PROMPT_WARNING_U2F_DEVICES" desc="Warning message which indicates that an extension has access to Universal 2nd Factor devices.">
         Access your Universal 2nd Factor devices
       </message>
       <message name="IDS_EXTENSION_PROMPT_WARNING_WEB_CONNECTABLE" desc="Permission string for allowing websites to connect to extensions.">
         Communicate with cooperating websites
       </message>
 
+      <!-- Install related messages. Please keep alphabetized. -->
+      <message name="IDS_EXTENSION_INSTALL_PROCESS_CRASHED" desc="Error message in case package fails to install because a utility process crashed.">
+        Could not install package because a utility process crashed. Try restarting Chrome and trying again.
+      </message>
+      <message name="IDS_EXTENSION_PACKAGE_ERROR_CODE" desc="Error message in cases where we fail to install the extension because the crx file is invalid. For example, because the crx header or signature is invalid.">
+        Package is invalid: '<ph name="ERROR_CODE">$1<ex>error</ex></ph>'.
+      </message>
+      <message name="IDS_EXTENSION_PACKAGE_ERROR_MESSAGE" desc="The cases where we get an error message string back from some other component. The message might be in English, but these are typically developer errors, and the extension SDK is English.">
+        Package is invalid. Details: '<ph name="ERROR_MESSAGE">$1<ex>error</ex></ph>'.
+      </message>
+      <message name="IDS_EXTENSION_PACKAGE_INSTALL_ERROR" desc="Error message in case package fails to install because of some problem with the filesystem.">
+        Could not install package: '<ph name="ERROR_CODE">$1<ex>error</ex></ph>'
+      </message>
+      <if expr="is_win">
+        <message name="IDS_EXTENSION_UNPACK_FAILED" desc="On windows, it is possible to mount a disk without the root of that disk having a drive letter.  The sandbox does not support this. See crbug/49530 .">
+          Can not unpack extension.  To safely unpack an extension, there must be a path to your profile directory that starts with a drive letter and does not contain a junction, mount point, or symlink.  No such path exists for your profile.
+        </message>
+      </if>
+      <if expr="not is_win">
+        <message name="IDS_EXTENSION_UNPACK_FAILED" desc="">
+          Can not unpack extension.  To safely unpack an extension, there must be a path to your profile directory that does not contain a symlink.  No such path exists for your profile.
+        </message>
+      </if>
     </messages>
   </release>
 </grit>