am cf686f7a: Revert "Support a prebuilt WebView."

* commit 'cf686f7adb1cbc4efe3e93ae69b040d328b0e23f':
  Revert "Support a prebuilt WebView."
tree: 5c39d4cbcd40f0e879c5a38ce90928dadff5b252
  1. Android.mk
  2. chromium/