Avoid last param to CTFontCreateWithGraphicsFont.

Avoid last param to CTFontCreateWithGraphicsFont.

The last parameter of CTFontCreateWithGraphicsFont (CTFontDescriptorRef
attributes) *must* be nullptr. If non-nullptr then with fonts with
variation axes, the copy will fail in CGFontVariationFromDictCallback
when it assumes kCGFontVariationAxisName is CFNumberRef which it quite
obviously is not.

TBR=reed@google.com
Blocking dev builds, just removes code.

BUG=chromium:535109
Committed: https://skia.googlesource.com/skia/+/0584631f5254add2f85d94f788d9d6115509211e

[bungeman-skia, 2015-09-23 18:01:55]

The CQ bit was checked by bungeman@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-09-23 18:02:13]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1362053003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1362053003/1

[bungeman-skia, 2015-09-23 18:10:22]

bungeman@google.com changed reviewers:
+ mtklein@google.com, reed@google.com

[bungeman-skia, 2015-09-23 18:10:22]

Unsurprisingly the work around for the issue in CoreText uncovered what appears
to be a bug in CoreGraphics. Hopefully removing all of this doesn't uncover more
bugs.

[commit-bot: I haz the power, 2015-09-23 18:35:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-23 18:35:50]

Dry run: This issue passed the CQ dry run.

[bungeman-skia, 2015-09-23 19:50:35]

The CQ bit was checked by bungeman@google.com

[commit-bot: I haz the power, 2015-09-23 19:50:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1362053003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1362053003/1

[commit-bot: I haz the power, 2015-09-23 19:51:31]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/0584631f5254add2f85d94f788d9d6115509211e