Remove document.write reference in sandboxing docs.

chrome/common/extensions/docs/templates/articles/app_external.html

 <h1>External Content</h1>
 
 
 <p>
 The <a href="app_architecture.html#security">Chrome Apps security model</a> disallows
 external content in iframes and
 the use of inline scripting and <code>eval()</code>.
 You can override these restrictions,
 but your external content must be isolated from the app.
 </p>
@@ skipping 123 matching lines @@
 It's a trade-off though:
 sandboxed pages can't use the chrome.* APIs.
 If you need to do things like <code>eval()</code>,
 go this route to be exempt from CSP,
 but you won't be able to use the cool new stuff.
 </p>
 
 <h3 id="inline_scripts">Use inline scripts in sandbox</h3>
 
 <p>
-Here's a sample sandboxed page
-which uses an inline script and <code>eval()</code>:
+Here's a sample sandboxed page which uses an inline script and <code>eval()</code>:
 </p>
 
 <pre data-filename="sandboxed.html">
 &lt;html>
   &lt;body>
     &lt;h1>Woot&lt;/h1>
     &lt;script>
-      document.write('I am an inline script.&lt;br>');
-      eval('document.write(\'I am an eval-ed inline script.\');');
+      eval('console.log(\'I am an eval-ed inline script.\')');
     &lt;/script>
   &lt;/body>
 &lt;/html>
 </pre>
 
 <h3 id="include_sandbox">Include sandbox in manifest</h3>
 
 <p>
 You need to include the <code>sandbox</code> field in the manifest
 and list the app pages to be served in a sandbox:
@@ skipping 125 matching lines @@
 
 <pre data-filename="sandboxed.html">
 var messageHandler = function(e) {
   console.log('Background script says hello.', e.data);
 };
 
 window.addEventListener('message', messageHandler);
 </pre>
 
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