Add "enable_desktop_capturer" build flag (#13133)

* Make it possible to disable a module for a renderer

* Put DesktopCapturer API under a build flag

The name is "enable_desktop_capturer".
Enabled by default.

lib/browser/init.js

@@ -153,8 +153,11 @@ app.setAppPath(packagePath)
 // Load the chrome extension support.
 require('./chrome-extension')
 
-// Load internal desktop-capturer module.
-require('./desktop-capturer')
+const features = process.atomBinding('features')
+if (features.isDesktopCapturerEnabled()) {
+  // Load internal desktop-capturer module.
+  require('./desktop-capturer')
+}
 
 // Load protocol module to ensure it is populated on app ready
 require('./api/protocol')