title: PAC support disabled because there is no system implementation
body: <p>I've recently upgraded my Nexus 4 to Android 4.4. Whilst debugging my app, I discovered message <code>W/chromium(14962): [WARNING:proxy_service.cc(888)] PAC support disabled because there is no system implementation</code></p>
  
  <p>What does it mean ?</p>
  
  <hr>
  
  <p><strong>Logcat</strong></p>
  
  <pre><code>12-12 17:38:56.726: V/WebViewChromium(14962): Binding Chromium to the main looper Looper{41f91588}
  12-12 17:38:56.736: I/chromium(14962): [INFO:library_loader_hooks.cc(112)] Chromium logging enabled: level = 0, default verbosity = 0
  12-12 17:38:56.736: I/BrowserProcessMain(14962): Initializing chromium process, renderers=0
  12-12 17:38:56.746: W/chromium(14962): [WARNING:proxy_service.cc(888)] PAC support disabled because there is no system implementation
  </code></pre>