docs: update the links to the get-the-code page to use the https url

This patch changes all the links to the get-the-code web page to use the
safer https url version.

BUG=None
[email protected]

Review URL: https://codereview.chromium.org/1756483006

Cr-Commit-Position: refs/heads/master@{#379260}
diff --git a/docs/closure_compilation.md b/docs/closure_compilation.md
index 2f0907ab..931029c 100644
--- a/docs/closure_compilation.md
+++ b/docs/closure_compilation.md
@@ -39,7 +39,7 @@
 ## Assumptions
 
 A working Chrome checkout. See here:
-http://www.chromium.org/developers/how-tos/get-the-code
+https://www.chromium.org/developers/how-tos/get-the-code
 
 ## Typechecking Your Javascript