Hoist/fold GraphicsContext::DrawTiledImage (border-image version)

Folds the "border-image version" of GraphicsContext::DrawTiledImage into
NinePieceImagePainter. This should hopefully allow for better control of
tiling computations, and also seems like a better place from a layering

The computation of <scale, phase, spacing> is refactored into a new
function ComputeTileParameters.

Switch from using Image::TileRule to using ENinePieceImageRule (the
style type), and remove the former since it is no longer used.

Bug: 614125
Change-Id: Ia7433f871bb0bc6f7f963a14ae49b898559860d2
Reviewed-on: https://chromium-review.googlesource.com/c/1448612
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628278}
8 files changed