Updates source.android.com for external contributions to WebKit

Instructs external contributors that changes to external/webkit should be made
directly at webkit.org.

I've assumed that in the future we will (or should now) direct external
contributors to make changes upstream for other upstream projects too.

Change-Id: I538930794907729ebcca4cbb20a2952d0159873f
diff --git a/pdk/docs/source/submit-patches.jd b/pdk/docs/source/submit-patches.jd
index 2b7bae1..b9b11fa 100644
--- a/pdk/docs/source/submit-patches.jd
+++ b/pdk/docs/source/submit-patches.jd
@@ -14,6 +14,9 @@
 Open Source community, see <a href="{@docRoot}source/roles.html">Project roles</a>.</li>
 <li>If you plan to contribute code to the Android platform, be sure to read
 the <a href="{@docRoot}source/licenses.html">AOSP's licensing information</a>.</li>
+<li>Note that changes to some of the upstream projects used by Android should be
+made directly to that project, as described in
+<a href="#upstream-projects">Upstream Projects</a>.
 </ul>
 <h2>
 Working with the code</h2>
@@ -142,6 +145,24 @@
 .<br><br><h2>
 Using GitWeb to track patch histories</h2>
 To view snapshots of the files that are in the public Android repositories and view file histories, use the <a href="http://android.git.kernel.org/">Android instance of GitWeb</a>
-.<br></div>
+.<br>
+<h2><a name="upstream-projects"></a>Upstream Projects</h2>
+Android makes use of a number of other open-source projects, such as the Linux
+kernel and WebKit, as described in
+<a href="{@docRoot}source/code-lines.html">Branches &amp Releases</a>. For the
+upstream projects detailed below, changes should be made directly upstream. Such
+changes will be incorporated into the Android tree as part of the usual process
+of pulling these projects.
+<h3>WebKit</h3>
+All changes to the WebKit project at <code>external/webkit</code> should be made
+upstream at <a href="http://www.webkit.org">http://www.webkit.org</a>. The
+process begins by filing a WebKit bug. This bug should use <code>Android</code>
+for the <code>Platform</code> and <code>OS</code> fields only if the bug is
+specific to Android. Bugs are far more likely to receive the reviewers'
+attention once a proposed fix is added and tests are included. See
+<a href="http://webkit.org/coding/contributing.html">Contributing Code to
+WebKit</a> for details.
+<br>
+</div>
 </div>
 </div>