Added isComputedStyle::isDisplayTableType() and made it static

Removed EDisplay FIRST_TABLE_DISPLAY and LAST_TABLE_DISPLAY from
EDisplay, and moved them to a static function isDisplayTableType() on
ComputedStyle. Also made the similar functions like this static
functions, since they should have been static all along.

BUG=628043

Review-Url: https://codereview.chromium.org/2365263002
Cr-Commit-Position: refs/heads/master@{#421749}
3 files changed