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

<div id="pageData-name" class="pageData">BrowsingData API</div>

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<p id="classSummary">
  Use the <code>chrome.browsingData</code> module to remove browsing data from a
  user's local profile.
</p>

<h2 id="manifest">Manifest</h2>

<p>
  You must declare the "browsingData" permission in the
  <a href="manifest.html">extension manifest</a> to use this API.
</p>

<pre>{
  "name": "My extension",
  ...
  <b>"permissions": [
    "browsingData",
  ]</b>,
  ...
}</pre>

<h2 id="usage">Usage</h2>

<p>
  The simplest use-case for this API is a a time-based mechanism for clearing a
  user's browsing data. Your code should provide a timestamp which indicates the
  historical date after which the user's browsing data should be removed. This
  timestamp is formatted as the number of milliseconds since the Unix epoch
  (which can be retrieved from a JavaScript <code>Date</code> object via the
  <code>getTime</code> method).
</p>

<p>
  For example, to clear all of a user's browsing data from the last week, you
  might write code as follows:
</p>

<pre>var callback = function () {
  // Do something clever here once data has been removed.
};

var millisecondsPerWeek = 1000 * 60 * 60 * 24 * 7;
var oneWeekAgo = (new Date()).getTime() - millisecondsPerWeek;
chrome.browsingData.remove({
  "since": oneWeekAgo
}, {
  "appcache": true,
  "cache": true,
  "cookies": true,
  "downloads": true,
  "fileSystems": true,
  "formData": true,
  "history": true,
  "indexedDB": true,
  "localStorage": true,
  "pluginData": true,
  "passwords": true,
  "webSQL": true
}, callback);</pre>

<p>
  The <code>chrome.browsingData.remove</code> method allows you to remove
  various types of browsing data with a single call, and will be much faster
  than calling multiple more specific methods. If, however, you only want to
  clear one specific type of browsing data (cookies, for example), the more
  granular methods offer a readable alternative to a call filled with JSON.
</p>

<pre>var callback = function () {
  // Do something clever here once data has been removed.
};

var millisecondsPerWeek = 1000 * 60 * 60 * 24 * 7;
var oneWeekAgo = (new Date()).getTime() - millisecondsPerWeek;
chrome.browsingData.removeCookies({
  "since": oneWeekAgo
}, callback);</pre>

<p class="caution">
  <strong>Important</strong>: Removing browsing data involves a good deal of
  heavy lifting in the background, and can take <em>tens of seconds</em> to
  complete, depending on a user's profile. You should use the callback mechanism
  to keep your users up to date on the removal's status.
</p>

<h2 id="origin_types">Origin Types</h2>

<p>
  Adding an <code>originType</code> property to the API's options object allows
  you to specify which types of origins ought to be effected. Currently, origins
  are divided into three categories:
</p>
<ul>
  <li>
    <code>unprotectedWeb</code> covers the general case of websites that users
    visit without taking any special action. If you don't specify an
    <code>originType</code>, the API defaults to removing data from unprotected
    web origins.
  </li>
  <li>
    <code>protectedWeb</code> covers those web origins that have been installed
    as hosted applications. Installing <a href="https://chrome.google.com/webstore/detail/aknpkdffaafgjchaibgeefbgmgeghloj">
    Angry Birds</a>, for example, protects the origin
    <code>http://chrome.angrybirds.com</code>, and removes it from the
    <code>unprotectedWeb</code> category. Please do be careful when triggering
    deletion of data for these origins: make sure your users know what they're
    getting, as this will irrevocably remove their game data. No one wants to
    knock tiny pig houses over more often than necessary.
  </li>
  <li>
    <code>extension</code> covers origins under the
    <code>chrome-extensions:</code> scheme. Removing extension data is, again,
    something you should be very careful about.
  </li>
</ul>
<p>
  We could adjust the previous example to remove only data from protected
  websites as follows:
</p>
<pre>var callback = function () {
  // Do something clever here once data has been removed.
};

var millisecondsPerWeek = 1000 * 60 * 60 * 24 * 7;
var oneWeekAgo = (new Date()).getTime() - millisecondsPerWeek;
chrome.browsingData.remove({
  "since": oneWeekAgo,
  <b>"originType": {
    "protectedWeb": true
  }</b>
}, {
  "appcache": true,
  "cache": true,
  "cookies": true,
  "downloads": true,
  "fileSystems": true,
  "formData": true,
  "history": true,
  "indexedDB": true,
  "localStorage": true,
  "pluginData": true,
  "passwords": true,
  "webSQL": true
}, callback);</pre>

<p class="caution">
  <strong>Seriously</strong>: Be careful with <code>protectedWeb</code> and
  <code>extension</code>. These are destructive operations that your users
  will write angry email about if they're not well-informed about what to
  expect when your extension removes data on their behalf.
</p>

<h2 id="samples">Examples</h2>
<p>
  Samples for the <code>browsingData</code> API are available
  <a href="http://code.google.com/chrome/extensions/trunk/samples.html#chrome.browsingData">on the samples page</a>.
</p>

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