[WebView] Remove dependency on FileUtils.

We implement our own version of deleteContents to
avoid depending on FileUtils, a hidden Android API.

BUG:18152150

Change-Id: I8607e36827bacc38a80a35f65c13f39f561551a0
1 file changed
tree: 1f01c8074741430720c51aa6f6f14ad358e03efd
  1. chromium/
  2. nullwebview/
  3. Android.mk