Fix various issues with Markdown docs

docs/chromoting_build_instructions.md

 # Chromoting Build Instructions
 
 Chromoting, also known as
 [Chrome Remote Desktop](https://support.google.com/chrome/answer/1649523),
 allows one to remotely control a distant machine, all from within the Chromium
 browser. Its source code is located in the `remoting/` folder in the Chromium
 codebase. For the sake of brevity, we'll assume that you already have a
 pre-built copy of Chromium (or Chrome) installed on your development computer.
 
 [TOC]
@@ skipping 18 matching lines @@
     1.  Choose `OAuth 2.0 client ID`.
     1.  Choose `Chrome App`.
     1.  Under application id, enter `ljacajndfccfgnfohlgkdphmbnpkjflk`.
 
 ## Obtain Chromium code
 
 If you've already checked out a copy of the browser's codebase, you can skip
 this section, although you'll still need to run `gclient runhooks` to ensure you
 build using the API keys you just generated.
 
-1.  Install the build dependencies, which are listed at
-    http://code.google.com/p/chromium/wiki/LinuxBuildInstructionsPrerequisites.
+1.  [Install the build dependencies](linux_build_instructions_prerequisites.md).
 1.  Install the depot\_tools utilities, a process that is documented at
     http://dev.chromium.org/developers/how-tos/install-depot-tools.
 1.  Download the Chromium source code by running:
     `$ fetch chromium --nosvn=True`
 
 ## Build and install the Linux host service
 
 If you want to remote into a (Debian-based) GNU/Linux host, follow these steps
 to compile and install the host service on that system. As of the time of
 writing, you must compile from source because no official binary package is
@@ skipping 53 matching lines @@
         account if you weren't already.
 
 ## Build and install the Android client
 
 If you want to use your Android device to connect to your Chromoting hosts,
 follow these steps to install the client app on it. Note that this is in the
 very early stages of development. At the time of writing, you must compile from
 source because no official version is being distributed.
 
 1.  Follow all the instructions under the `Getting the code` and
-    `Install prerequisites` sections of: TODO: 404
-    http://code.google.com/p/chromium/wiki/AndroidBuildInstructions
+    `Install prerequisites` sections of:
+    https://www.chromium.org/developers/how-tos/android-build-instructions
 1.  Move into the `src/` directory that contains your checkout of the Chromium
     code.
 1.  Build the Android app: `$ ninja -C out/Release remoting_apk`
 1.  Connect your device and set up USB debugging:
     1.  Plug your device in via USB.
     1.  Open the Settings app and look for the `Developer options` choice.
         1.  If there is no such entry, open `About phone`, tap `Build number`
             7 times, and look again.
     1.  Under `Developer options`, toggle the main switch to `ON` and enable
         `USB debugging`.
 1.  On your machine and still in the `src/` directory, run:
     `$ build/android/adb_install_apk.py --apk=out/Release/apks/Chromoting.apk`
 1.  If your Android device prompts you to accept the host's key, do so.
 1.  The app should now be listed as Chromoting in your app drawer.
 
 See the [chromoting_android_hacking.md] guide for instructions on viewing the
 Android app's log and attaching a debugger.