Implement Android WebView BlockNetworkImages

This uses the WebCore ImagesEnabled setting, which is added to
ContentSettings. The setting also includes overriding
WebPermissionClient::allowImage, which here allows images with local
soucres to load as well.

Use a whitelist of local file schemes instead of blacklisting only
http(s).

BUG=


Review URL: https://chromiumcodereview.appspot.com/10920033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@158809 0039d316-1c4b-4281-b951-d872f2087c98
6 files changed