Split initial methods of (/max/min)(width/height) on ComputedStyle.

- width and height share the same initial method InitialSize
- minWidth and minHeight share the same initial method InitialMinSize
- maxWidth and maxHeight share the same initial method InitialMaxSize

This patch makes each of those properties use its own initial method so
that they can be more easily generated (the generator does not support
sharing of initial methods).

Diff of generated files:


Review-Url: https://codereview.chromium.org/2841353002
Cr-Commit-Position: refs/heads/master@{#467603}
4 files changed