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

Folds the "background-image version" of GraphicsContext::DrawTiledImage
into BoxPainter(Base). Mostly a verbatim move of said method and
Image::DrawTiledBackground (the real "meat") an the associated helpers.

This also introduces the intended replacement (for versions of this
method): GraphicsContext::DrawImageTiled.

Calls to StartAnimation are moved into the implementations of
Image::DrawPattern as needed.

Bug: 614125
Change-Id: Ib04daa5abce9c61c12f4a8297920ea25760557cf
Reviewed-on: https://chromium-review.googlesource.com/c/1448458
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@{#628136}
6 files changed