docs: Add developer guide cross-references, Project ACRE, round 4

Change-Id: I1b43414aaec8ea217b39a0d780c80a25409d0991
diff --git a/test-runner/src/android/test/mock/package.html b/test-runner/src/android/test/mock/package.html
index 0f1bc6f..29b2d80 100644
--- a/test-runner/src/android/test/mock/package.html
+++ b/test-runner/src/android/test/mock/package.html
@@ -1,5 +1,10 @@
 <HTML>
 <BODY>
-Utility classes providing stubs or mocks of various Android framework building blocks.
+<p>Utility classes providing stubs or mocks of various Android framework building blocks.</p>
+
+<p>For more information, see the
+<a href="{@docRoot}guide/topics/testing/index.html">Testing</a> developer guide.</p>
+{@more}
+
 </BODY>
 </HTML>