Allow fractional letter- word-spacing values.

Allow fractional letter- and word-spacing values.

Previously, fractional values specified or calculated for letter- and word-
spacing were truncated to an integer, despite our ability to draw text with
floating point precision. Exposing this ability is as simple as changing the
data structures involved to store floats.

BUG=154289
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=153727

[leviw_travelin_and_unemployed, 2013-07-08 16:33:46]

I've verified that we support fractional word and letter spacing when drawing
fonts on all platforms, we just need to update the data structures. FFX and IE
support this already.

[eae, 2013-07-08 16:38:33]

LGTM

[commit-bot: I haz the power, 2013-07-08 16:38:52]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/leviw@chromium.org/18332019/17001

[commit-bot: I haz the power, 2013-07-08 16:48:27]

Retried try job too often on blink_presubmit for step(s) presubmit
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=blink_pres...

[leviw_travelin_and_unemployed, 2013-07-08 16:55:44]

Adding abarth for the Source/WebKit/chromium/src/WebFontImpl.* change.

[jamesr, 2013-07-08 17:39:21]

On windows, at least, Font::drawGlyphs() computes integer advances for each
glyph within the run since that's all GDI can handle.  How would these
properties do anything interesting on that platform?

[leviw_travelin_and_unemployed, 2013-07-08 17:49:16]

On 2013/07/08 17:39:21, jamesr wrote:
> On windows, at least, Font::drawGlyphs() computes integer advances for each
> glyph within the run since that's all GDI can handle.  How would these
> properties do anything interesting on that platform?

We accumulate the location of glyphs using floats, so this still effects
placement when the fractions accumulate over integer boundaries.

[jamesr, 2013-07-08 20:56:02]

Ah yes, of course.  lgtm

[commit-bot: I haz the power, 2013-07-08 21:04:36]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/leviw@chromium.org/18332019/17001

[commit-bot: I haz the power, 2013-07-08 22:25:37]

Sorry for I got bad news for ya.
Compile failed with a clobber build on mac_layout_rel.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=mac_layout...
Your code is likely broken or HEAD is junk. Please ensure your
code is not broken then alert the build sheriffs.
Look at the try server FAQ for more details.

[commit-bot: I haz the power, 2013-07-08 22:38:12]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/leviw@chromium.org/18332019/17001

[commit-bot: I haz the power, 2013-07-09 00:10:19]

Change committed as 153727