Explicitly invalidate LayoutView when overflow is recalculated.

Explicitly invalidate LayoutView when overflow is recalculated.

This bug occurs because during an animation we may change the amount of layout
overflow (via FrameView::recalcOverflowAfterStyleChange). Previously, this
would cause a change in scrollbar existance until r432965 made it so that the
FrameView would prevent scrollbar creation earlier in cases where they're known
to be unneeded. Changing scrollbar existence causes a layout so we'd implicitly
invalidate and repaint. Since that change, we (correctly) don't bother doing a
layout but because of that we no longer invalidate so the additionally exposed
background region doesn't get painted.

BUG=683814
Review-Url: https://codereview.chromium.org/2685883004
Cr-Commit-Position: refs/heads/master@{#452170}
(cherry picked from commit 717789e00f9ff34efe3a2ca23ebd69e802d8b6ec)

[bokan, 2017-03-14 21:07:19]

Description was changed from

==========
Explicitly invalidate LayoutView when overflow is recalculated.

This bug occurs because during an animation we may change the amount of layout
overflow (via FrameView::recalcOverflowAfterStyleChange). Previously, this
would cause a change in scrollbar existance until r432965 made it so that the
FrameView would prevent scrollbar creation earlier in cases where they're known
to be unneeded. Changing scrollbar existence causes a layout so we'd implicitly
invalidate and repaint. Since that change, we (correctly) don't bother doing a
layout but because of that we no longer invalidate so the additionally exposed
background region doesn't get painted.

BUG=683814

Review-Url: https://codereview.chromium.org/2685883004
Cr-Commit-Position: refs/heads/master@{#452170}
(cherry picked from commit 717789e00f9ff34efe3a2ca23ebd69e802d8b6ec)
==========

to

==========
Explicitly invalidate LayoutView when overflow is recalculated.

This bug occurs because during an animation we may change the amount of layout
overflow (via FrameView::recalcOverflowAfterStyleChange). Previously, this
would cause a change in scrollbar existance until r432965 made it so that the
FrameView would prevent scrollbar creation earlier in cases where they're known
to be unneeded. Changing scrollbar existence causes a layout so we'd implicitly
invalidate and repaint. Since that change, we (correctly) don't bother doing a
layout but because of that we no longer invalidate so the additionally exposed
background region doesn't get painted.

BUG=683814

Review-Url: https://codereview.chromium.org/2685883004
Cr-Commit-Position: refs/heads/master@{#452170}
(cherry picked from commit 717789e00f9ff34efe3a2ca23ebd69e802d8b6ec)
==========