[Docs] Add wiki content to Markdown docs

docs/how_to_contribute.md

Index: docs/how_to_contribute.md
diff --git a/docs/how_to_contribute.md b/docs/how_to_contribute.md
new file mode 100644
index 0000000000000000000000000000000000000000..5a232cc5784919cf49aee073977931da4e84780a
--- /dev/null
+++ b/docs/how_to_contribute.md
@@ -0,0 +1,26 @@
+# How to get an LSS change committed
+
+## Review
+
+You get your change reviewed, you can upload it to
+http://codereview.chromium.org (Rietveld) using `git cl upload` from Chromium's
+`depot-tools`.
+
+## Testing
+
+Unfortunately, LSS has no automated test suite.
+
+You can test LSS by patching it into Chromium, building Chromium, and running
+Chromium's tests. (See [ProjectsUsingLSS](projects_using_lss.md).)
+
+You can compile-test LSS by running:
+
+    gcc -Wall -Wextra -Wstrict-prototypes -c linux_syscall_support.h
+
+## Rolling into Chromium
+
+If you commit a change to LSS, please also commit a Chromium change to update
+`lss_revision` in Chromium's DEPS file.
+
+This ensures that the LSS change gets tested, so that people who commit later
+LSS changes don't run into problems with updating `lss_revision`.