Reduce test code duplication in fast/forms/file

Factor out some repeatedly used functions when dragging files onto
type=file elements.

R=
BUG=

Review URL: https://codereview.chromium.org/148983008

git-svn-id: svn://svn.chromium.org/blink/trunk@166782 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove dead code in modules/geolocation/.

This CL removes:
- Coordinates::isolatedCopy
- GelocationClient::provideGeolocationTo declaration
- Geoposition::isolatedCopy

BUG=none
TEST=none; no behavior changes.

Review URL: https://codereview.chromium.org/158603002

git-svn-id: svn://svn.chromium.org/blink/trunk@166783 bbb929c8-8fbe-4397-9dbb-9b2b20218538