Updated preferences and proxy settings API documentation

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

Index: chrome/common/extensions/docs/static/preferences.html
diff --git a/chrome/common/extensions/docs/static/preferences.html b/chrome/common/extensions/docs/static/preferences.html
new file mode 100644
index 0000000000000000000000000000000000000000..3db50986f7f54bd5ac12a246b62dbfc829953289
--- /dev/null
+++ b/chrome/common/extensions/docs/static/preferences.html
@@ -0,0 +1,90 @@
+<div id="pageData-name" class="pageData">Preferences</div>
+
+<!-- BEGIN AUTHORED CONTENT -->
+<p id="classSummary">
+The <code>chrome.preferences</code> module contains a prototype for giving other
+modules access to manage preferences stored by Chrome. This prototype is used,
+for example, for <a
+  href="proxy.html#property-settings"><code>chrome.proxy.settings</code></a>.
+</p>
+
+<h2 id="description">Overview</h2>
+
+<p>
+The preferences API provides a common set of functions
+(<code>get()</code>, <code>set()</code>, and <code>clear()</code>) as
+well as an event publisher (<code>onChange</code>) for various
+preferences in Chrome. The <a href="proxy.html#overview-examples">proxy settings
+ examples</a> demonstrate how these functions are intended to be used.
+</p>
+
+<!--
+<h2 id="lifecycle">Life cycle of preferences</h2>
+
+<p>
+The life cycle of preferences depends on whether they are set for regular or
+incognito profiles. </p>
+-->
+
+<p>
+Currently, preferences can only be set for regular profiles. Once set, they
+remain in place until they are cleared by the governing extension, or the
+governing extension is disabled or uninstalled.
+</p>
+
+<h2 id="precedence">Precedence</h2>
+
+<p>
+Chrome manages preferences on different layers. The following list describes the
+layers that may influence the effective preferences, in increasing order of
+precedence.
+<ol>
+  <li>System preferences provided by the operating system</li>
+  <li>Command-line parameters</li>
+  <li>Preferences set by extensions</li>
+  <li>Policies</li>
+</ol>
+</p>
+
+<p>
+As the list implies, policies might overrule any changes that you specify with
+your extension.
+</p>
+
+<!--
+<p>
+As discussed above, Chrome allows using different preferences for regular
+windows and incognito windows. The following example illustrates the behavior.
+Assume that no policy overrides the preferences and that an extension can set
+preferences for regular windows <b>(R)</b> and preferences for incognito windows
+<b>(I)</b>.
+</p>
+
+<p>
+<ul>
+  <li>If only <b>(R)</b> is set, these preferences are effective for both
+  regular and incognito windows.</li>
+  <li>If only <b>(I)</b> is set, these preferences are effective for only
+  incognito windows. Regular windows use the preferences determined by the lower
+  layers (command-line options and system settings).</li>
+  <li>If both <b>(R)</b> and <b>(I)</b> are set, the respective preferences are
+  used for regular and incognito windows.</li>
+</ul>
+</p>
+-->
+
+<p>
+If two or more extensions want to set the same preference to different values,
+the extension installed most recently takes precedence over the other
+extensions.
+<!-- If the
+extension installed last sets only <b>(I)</b>, the preference of regular windows
+can be defined by previously installed extensions. -->
+</p>
+
+<p>
+The <em>effective</em> preference value is the setting that results from
+considering the preference rules. It is used by Chrome.
+<p>
+
+<!-- END AUTHORED CONTENT -->