Remove DerivedFontData::Create() in platform/fonts

As advised in [1], this CL removes unnecessary DerivedFontData::Create()
in //third_party/blink/renderer/platform/fonts and make their constructors
public, then make the callers use std::make_unique<DerivedFontData>
instead of it's Create() factory function.

[1] https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/iJ1bawbxbWs/vEdfT5QtBgAJ

Bug: 939691
Change-Id: I71825b2589c7cc25d2f1397d8ffa1aa4773558d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1527906
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Gyuyoung Kim <gyuyoung@igalia.com>
Cr-Commit-Position: refs/heads/master@{#641526}
2 files changed