cc: Correct expansion of invalidation for tiles outside of interest rect

cc: Correct expansion of invalidation for tiles outside of interest rect

Previously we subtracted the interest_rect_over_tiles from the
invalid_rect when looking to see what invalidation would not be recorded
but this computation is wrong.

Instead, we need to expand the invalidation to the bounds of the tiles
it touches (including tiles it touches on borders). Then we can subtract
the interest rect expanded to the bounds of tiles it touches (including
tiles it touches on borders). This makes each expansion match the
iteration of the given rect where we include borders.

If a tile is touched only on the border by invalidation, but the tile is
not touched even on a border by the interest rect, we want to expand the
invalidation to cover that tile.

TBR=enne, vmpstr
BUG=421729
Review URL: https://codereview.chromium.org/657913002

Cr-Commit-Position: refs/heads/master@{#299750}
(cherry picked from commit 04a24ab064c9e19d17d481b7649387a2ed2402ff)

Committed: https://chromium.googlesource.com/chromium/src/+/a28c3078ec897a97924dfb8bb853111a8743fe63

[danakj, 2014-10-22 17:00:27]

Committed patchset #1 (id:1) manually as
a28c3078ec897a97924dfb8bb853111a8743fe63 (presubmit successful).