[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
(cherry picked from commit 5112943866a77868d1987617ed1320e73e2a9ce4)
1 file changed
tree: 4145ad40716ab7f263cc84adf3e67d1b8a3f5550
  1. chromium/
  2. Android.mk