Adding stages for request headers and 3rd party attributes

chrome/common/extensions/docs/templates/intros/declarativeWebRequest.html

 <h2 id="notes">Notes</h2>
 
 <p>
 Use the <code>chrome.declarativeWebRequest</code> module to intercept, block, or
 modify requests in-flight. It is significantly faster than the <a
   href="webRequest.html"><code>chrome.webRequest</code> API</a> because you can
 register rules that are evaluated in the browser rather than the
 JavaScript engine which reduces roundtrip latencies and allows for very high
 efficiency.
 </p>
@@ skipping 121 matching lines @@
     <th>onBeforeSendHeaders
     <th>onHeadersReceived
     <th>onAuthRequired
   </tr>
   <tr><td>url<td>✓<td>✓<td>✓<td>✓
   <tr><td>resourceType<td>✓<td>✓<td>✓<td>✓
   <tr><td>contentType<td><td><td>✓<td>
   <tr><td>excludeContentType<td><td><td>✓<td>
   <tr><td>responseHeaders<td><td><td>✓<td>
   <tr><td>excludeResponseHeaders<td><td><td>✓<td>
+  <tr><td>requestHeaders<td><td>✓<td><td>

[vabr (Chromium), 2012/10/18 17:54:35]

I just appended all at the end, as it has not been in alphabetical order. Feel
free to let me know, if I should re-order it, though.

+  <tr><td>excludeRequestHeaders<td><td>✓<td><td>
+  <tr><td>thirdPartyForCookies<td>✓<td>✓<td>✓<td>✓
   <tr>
     <th colspan="5" style="padding-top:2em">Request stages during which actions can be executed.
   </tr>
   <tr>
     <th>Event
     <th>onBeforeRequest
     <th>onBeforeSendHeaders
     <th>onHeadersReceived
     <th>onAuthRequired
   </tr>
@@ skipping 61 matching lines @@
 chrome.declarativeWebRequest.onRequest.addRules([rule1, rule2]);
 </pre>
 
 <p>
 It is important to recognize that the <code>IgnoreRules</code> action is not
 persisted across <a href="#evaluation">request stages</a>. All conditions of
 all rules are evaluated at each stage of a web request. If an
 <code>IgnoreRules</code> action is executed, it applies only to other actions
 that are executed for the same web request in the same stage.
 </p>