Document the new external extensions path on Mac OS.

chrome/common/extensions/docs/static/external_extensions.html

 <div id="pageData-name" class="pageData">Other Deployment Options</div>
 <div id="pageData-showTOC" class="pageData">true</div>
 
 <p>
 Usually, users install their own extensions.
 But sometimes you might want an extension
 to be installed automatically.
 Here are two typical cases:
 </p>
 
@@ skipping 74 matching lines @@
 
 </p>
 
 <ol>
 <li>If you are installing from a file, make the <code>.crx</code> extension
 file available to the machine you want to install the extension on.
 (Copy it to a local directory or to a network share for example,
 <code>\\server\share\extension.crx</code>
 or <code>/home/share/extension.crx</code>.)
 </li>
-<li>Locate the <code>external_extensions.json</code> file
-  under the Google Chrome installation directory.
+<li>Locate the <code>external_extensions.json</code> file.
   If the file doesn't exist, create it.
   The location depends on the operating system.
   <dl>
   <dt> Windows: </dt>
     <dd> <code><em>chrome_root</em>\Application\<em>chrome_version</em>\Extensions\</code>
     <br />
     Example: <code>c:\Users\Me\AppData\Local\Google\Chrome\Application\6.0.422.0\Extensions\</code>
     </dd>
   <dt> Mac OS X: </dt>
-    <dd> <code>/Applications/Google Chrome.app/Contents/Extensions/</code> </dd>
+    <dd> <code>/Library/Application Support/Google/Chrome/External Extensions/</code> </dd>
+    <p class="note"><b>Note:</b> The external extensions file is read only if every directory in the path is owned by the user <code>root</code>, has the group <code>admin</code>, and is not world readable.  The path must also be free of symbolic links.  These restrictions prevent an unprivileged user from causing extensions to be installed for all users.  See <a href="#troubleshooting">troubleshooting</a> for details.</p>
+    <p class="note">
+    <b>Note:</b> The above path was added in Chrome 16.  Prior versions used a different path, which is now deprecated:
+    <code>/Applications/Google Chrome.app/Contents/Extensions/</code> .</p>
   <dt> Linux: </dt>
     <dd> <code>/opt/google/chrome/extensions/</code> <br>
     <b>Note:</b> Use <code>chmod</code> if necessary
     to make sure that <code>extensions/external_extensions.json</code>
     is world-readable.
     </dd>
   </dl>
 </li>
 <li> Add an entry to <code>external_extensions.json</code>
 for your extension's ID.  If you are installing from a file, specify the
@@ skipping 26 matching lines @@
     "external_update_url": "http://myhost.com/mytestextension/updates.xml"
   }
 }</pre>
 </li>
 
 <li>Save the JSON file. </li>
 <li>Launch Google Chrome and go to <b>chrome://extensions</b>;
 you should see the extension listed. </li>
 </ol>
 
+<h3 id="troubleshooting">Troubleshooting Mac OS permissions problems</h3>
+
+On Mac OS, if you do not see the external extension installed when Chrome is launched, there may be a permissions problem with the external extensions preferences file.  To see if this is the problem, follow these steps:

[kathyw, 2011/09/30 15:29:04]

Oops, I missed one before: Add <p> tags around this paragraph.

+
+<ol>
+  <li> Launch the Console program.  You can find it under /Applications/Utilities/Console. </li>
+  <li> If the leftmost icon in the Console says "Show Log List", click that icon.  A second column appears at the left. </li>
+  <li> Click "Console Messages" in the left pane. </li>
+  <li> Search for the string <b>Can not read external extensions</b>.  If there is a problem reading the external extensions file, you will find an error message.  Look for another error message directly above it, which should explain the issue.  For example, if you see the following error:
+     "Path /Library/Application Support/Google/Chrome is owned by the wrong group", you need to use <code>chgrp</code> or the Finder's Get Info dialog to change the directory's group owner to the Administrator group.</li>
+  <li> After fixing the issue, relaunch Chrome.  Test that the external extension is now installed.  It is possible that one permissions error keeps Chrome from detecting a second error.  If the external extension was not installed, repeat these steps until you do not see an error in the Console application.
+</ol>
+
 <h2 id="registry">Using the Windows registry</h2>
 
 <ol>
 <li>Make the <code>.crx</code> extension file available
 to the machine you want to install the extension on.
 (Copy it to a local directory or to a network share &mdash;
 for example, <code>\\server\share\extension.crx</code>.)
 </li>
 <li>Find or create the following key in the
 registry:
@@ skipping 101 matching lines @@
 
 <br>
 
 <p><b>How do I get off the blacklist?</b> </p>
 <p>If the user uninstalls your extension, you should respect that
 decision. However, if you (the developer) accidentally uninstalled
 your extension through the UI,
 you can remove the blacklist tag
 by installing the extension normally
 through the UI, and then uninstalling it. </p>