VTTCue: Make position/line/size double attributes

Changing the IDL types of the attribute to match the specification.
Convert all internal storage associated with the attributes into floats
(from integers).
Add a test (vtt-cue-float-precision.html) to show that the storing as
single precision is intentional.

BUG=448000

Review URL: https://codereview.chromium.org/857823003

git-svn-id: svn://svn.chromium.org/blink/trunk@188663 bbb929c8-8fbe-4397-9dbb-9b2b20218538
5 files changed
tree: c1c0d0121e33d18a6f5685d10d84a5cb21f4c1b2
  1. third_party/