[css-grid] Properly reset auto repeat style attributes

[css-grid] Properly reset auto repeat style attributes

All the auto repeat attributes stored in ComputedStyle were not properly
initialized/set up whenever initial or inherit were used in
grid-template-{columns|rows}. This means that any previous value would be
incorrectly used by the grid layout logic like for example to compute the
number of auto repeat tracks.

This was causing crashes as we were trying to access invalid indexes in the
Vectors storing the style information for tracks.

BUG=722054
Review-Url: https://codereview.chromium.org/2885003002
Cr-Original-Commit-Position: refs/heads/master@{#472396}
Review-Url: https://codereview.chromium.org/2896533003 .
Cr-Commit-Position: refs/branch-heads/3071@{#627}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/e50c18655716345368c5d6ce1c3c954546ac585b

[svillar, 2017-05-19 08:38:31]

Description was changed from

==========
[css-grid] Properly reset auto repeat style attributes

All the auto repeat attributes stored in ComputedStyle were not properly
initialized/set up whenever initial or inherit were used in
grid-template-{columns|rows}. This means that any previous value would be
incorrectly used by the grid layout logic like for example to compute the
number of auto repeat tracks.

This was causing crashes as we were trying to access invalid indexes in the
Vectors storing the style information for tracks.

BUG=722054

Review-Url: https://codereview.chromium.org/2885003002
Cr-Commit-Position: refs/heads/master@{#472396}
(cherry picked from commit b3a11019e6709be450e8dc92130e53920c0e5717)
==========

to

==========
[css-grid] Properly reset auto repeat style attributes

All the auto repeat attributes stored in ComputedStyle were not properly
initialized/set up whenever initial or inherit were used in
grid-template-{columns|rows}. This means that any previous value would be
incorrectly used by the grid layout logic like for example to compute the
number of auto repeat tracks.

This was causing crashes as we were trying to access invalid indexes in the
Vectors storing the style information for tracks.

BUG=722054

Review-Url: https://codereview.chromium.org/2885003002
Cr-Original-Commit-Position: refs/heads/master@{#472396}
Review-Url: https://codereview.chromium.org/2896533003 .
Cr-Commit-Position: refs/branch-heads/3071@{#627}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/e50c18655716345368c5d6ce1c3c...
==========

[svillar, 2017-05-19 08:38:33]

Committed patchset #1 (id:1) manually as
e50c18655716345368c5d6ce1c3c954546ac585b.