VTTCue: Make position/line/size double attributes

LayoutTests/media/track/opera/track/webvtt/parsing/support/settings-line.vtt

Index: LayoutTests/media/track/opera/track/webvtt/parsing/support/settings-line.vtt
diff --git a/LayoutTests/media/track/opera/track/webvtt/parsing/support/settings-line.vtt b/LayoutTests/media/track/opera/track/webvtt/parsing/support/settings-line.vtt
index e95f3282cdddacebc5527296175895511159ad54..df275545e69bf3c199273add99ab87908e428c06 100644
--- a/LayoutTests/media/track/opera/track/webvtt/parsing/support/settings-line.vtt
+++ b/LayoutTests/media/track/opera/track/webvtt/parsing/support/settings-line.vtt
@@ -22,13 +22,13 @@ WEBVTT
 {"line":65536}
 
 00:00:00.000 --> 00:00:01.000 line:4294967296
-{"line":2147483647}
+{"line":2147483648}

[fs, 2015/01/19 15:19:32]

This caused by scanDigits clamping to INT_MAX - but a float can't represent
that, so you get the closest thing it can represent...

(When adding support for fractional percentage I suppose this will get bumped
again...)

[philipj_slow, 2015/01/20 10:07:38]

Acknowledged.

 
 00:00:00.000 --> 00:00:01.000 line:18446744073709552000
-{"line":2147483647}
+{"line":2147483648}
 
 00:00:00.000 --> 00:00:01.000 line:10000000000000000000000000000000000
-{"line":2147483647}
+{"line":2147483648}
 
 00:00:00.000 --> 00:00:01.000 line:65536%
 {}