Add a document to explain how to add a feature flag (chrome://flags)

[email protected]

Bug: N/A
Change-Id: I53bda41c047ed970417df5a5ca308855cbccbde5
Reviewed-on: https://chromium-review.googlesource.com/594754
Commit-Queue: Makoto Shimazu <[email protected]>
Reviewed-by: Nico Weber <[email protected]>
Cr-Commit-Position: refs/heads/master@{#492501}
diff --git a/docs/README.md b/docs/README.md
index 3ab2f4b..d13126d5 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -133,6 +133,8 @@
     more performant
 *   [ES6 Support in Chromium](es6_chromium.md) - Implementation of ECMAScript6
     features in Chromium
+*   [Adding a new feature flag in chrome://flags](how_to_add_your_feature_flag.md) - Quick
+    guide to add a new feature flag to experiment your feature.
 
 ### Testing
 *   [Running and Debugging Layout Tests](testing/layout_tests.md)