Move chrome.appWindow to chrome.app.window.

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

 <meta name="doc-family" content="apps">
 <div id="pageData-name" class="pageData">Manage App Lifecycle</div>
 <div id="pageData-showTOC" class="pageData">true</div>
 
 <p>
 The app runtime and event page are responsible
 for managing the app lifecycle.
 The app runtime manages app installation,
 controls the event page,
 and can shutdown the app at anytime.
@@ skipping 83 matching lines @@
 Panel windows are the same as shell windows,
 except they have different size and position restrictions,
 for example, a chat panel.
 </p>
 
 <p>Here's a sample <code>background.js</code>
   with a 'shell' window:</p>
 
 <pre>
 chrome.experimental.app.onLaunched.addListener(function() {
-  chrome.appWindow.create('main.html', {
+  chrome.app.window.create('main.html', {
     width: 800,
     height: 600,
     minWidth: 800,
     minHeight: 600,
     left: 100,
     top: 100,
     type: 'shell'
   });
 });
 </pre>
 
 <p>Here's a sample <code>background.js</code>
   with a 'panel' window:
 </p>
 
 <pre>
 chrome.experimental.app.onLaunched.addListener(function() {
-  chrome.appWindow.create('index.html', {
+  chrome.app.window.create('index.html', {
     width: 400,
     height: 200,
     type: 'panel'
   });
 });
 </pre>
 
 <h3>Including Launch Data</h3>
 
 <p>
@@ skipping 88 matching lines @@
 Keep the clean-up tasks synchronous and simple.
 </p>
 
 <pre>
 chrome.runtime.onSuspend.addListener(function() { 
   // Do some simple clean-up tasks.
 });
 </pre>
 
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