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

docs/mac_build_instructions.md

 # Mac Build Instructions
 
 [TOC]
 
 ## Prerequisites
 
 *   A Mac running 10.9+.
 *   [Xcode](https://developer.apple.com/xcode) 5+.
 *   [depot\_tools](http://dev.chromium.org/developers/how-tos/depottools).
 *   Install Xcode's "Command Line Tools" via Xcode menu -> Preferences ->
     Downloads
 *   The OSX 10.10 SDK. Run
     ```sh
     ls `xcode-select -p`/Platforms/MacOSX.platform/Developer/SDKs
     ```
     to check whether you have it. If you don't have it, you need to get one from
     an install of Xcode 6, and place it in the above directory.
 
 ## Getting the code
 
-[Check out the source code](http://dev.chromium.org/developers/how-tos/get-the-code)
+[Check out the source code](https://www.chromium.org/developers/how-tos/get-the-code)
 using Git.
 
 Before checking out, go to the
 [waterfall](http://build.chromium.org/buildbot/waterfall/) and check that the
 source tree is open (to avoid pulling a broken tree).
 
 The path to the build directory should not contain spaces (e.g. not
 `~/Mac OS X/chromium`), as this will cause the build to fail. This includes your
 drive name, the default "Macintosh HD2" for a second drive has a space.
 
@@ skipping 212 matching lines @@
 be set in `/etc/sysctl.conf`:
 
     echo kern.maxvnodes=$((512*1024)) | sudo tee -a /etc/sysctl.conf
 
 Or edit the file directly.
 
 If your `git --version` reports 2.6 or higher, the following may also improve
 performance of `git status`:
 
     git update-index --untracked-cache