Merge FontPlatformDataHarfBuzz and FontPlatformData headers

Merge FontPlatformDataHarfBuzz and FontPlatformData headers

Those two files were split apart and redundantly copied
for non-Mac and Mac platforms. This is an attempt an unifying
them, as a preparation for removing the CoreText shaper.
We can merge the implementations in FontPlatformDataHarfBuzz.cpp
and FontPlatformData.cpp as a next step.

This is a reland after the change got reverted again
in 7443ae0830de1c3483 due to Windows build breakge.

BUG=334269, 411287
R=eae,arv

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181655

[Dominik Röttsches, 2014-09-09 11:53:23]

One more try, could you take a look, Emil? The windows fix was to add the
minsubpixel field and methods to FontPlatformData.h.

[eae, 2014-09-09 15:58:11]

LGTM

[eae, 2014-09-09 15:58:16]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-09-09 15:58:55]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dominik.rottsches@intel.com/559433002/1

[commit-bot: I haz the power, 2014-09-09 16:02:31]

Committed patchset #1 (id:1) as 181655