Add documentation for the chrome.sockets API and manifest key.

chrome/common/extensions/docs/templates/articles/manifest/sockets.html

+<h1>sockets</h1>
+
+<p>
+The <code>sockets</code> manifest property declares which permissions are
+available for the <a href="../sockets_udp.html">chrome.sockets.udp</a>, <a href="../sockets_tcp.html">chrome.sockets.tcp</a> and <a href="../sockets_tcp_server.html">chrome.sockets.tcpServer</a> APIs.

[not at google - send to devlin, 2014/01/03 03:02:14]

ben wells did some work to make $ref's work from directories other than the
current one. you should be able to do $ref:socket.url $ref:socket.tcp etc.

also: try to keep < 80 characters. easier to edit + make review comments :)

[rpaquay, 2014/01/06 22:28:29]

Done.

+</p>
+
+<h2 id="manifest">Sample manifest.json</h2>
+<pre data-filename="manifest.json">
+{
+  "name": "My Sockets {{platform}}",
+  "sockets": {
+    "udp": {
+      // Permission for chrome.sockets.udp.send:
+      // The application is allowed to send udp packets
+      // to any host:port combination.
+      "send": "*"
+    },
+    "tcp": {
+      // Permission for chrome.sockets.tcp.connect:
+      // The application is allowed to connect only to the
+      // tcp server on 127.0.0.1 port 80.
+      "connect": "127.0.0.1:80"
+    },
+    "tcpServer": {
+      // Permission for chrome.sockets.tcpServer.listen:
+      // The application is allowed to accept new client
+      // connections on the local address at port 80.
+      "listen": "127.0.0.1:80"
+    }
+  },
+  ...
+}
+</pre>
+

[not at google - send to devlin, 2014/01/03 03:02:14]

this should probably go in its own <section>, see
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/common/exte...

[rpaquay, 2014/01/06 22:28:29]

This article follows the same pattern as "externally_connectable":
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/common/exte...

+<h2 id="reference">Reference</h2>
+<p class="api_reference">
+{{+partials.type type:apis.manifestTypes.byName.sockets/}}
+</p>