[ash-md] Stacks child layers properly for sticky header rows

[ash-md] Stacks child layers properly for sticky header rows

The CL implements sticky section header rows in VPN page. Care is taken
to stack the rows with child controls that have layers below the sticky
section header rows.

BUG=664244
TEST=Run with --material-design-ink-drop-animation-speed=slow
     Touch a Wi-Fi connection row and while ripple is growing
     drag-scroll the list of connections up.
     Verify that the ripple is stacked below the Wi-Fi header row.

Review-Url: https://codereview.chromium.org/2557333003
Cr-Commit-Position: refs/heads/master@{#438689}
(cherry picked from commit cd9913053dc56f12271b0c73558635ffbc26c580)

Committed: https://chromium.googlesource.com/chromium/src/+/7000b78c4fb63b02f48700904b8f6c44f828322c

[bruthig, 2016-12-22 22:29:21]

Description was changed from

==========
[ash-md] Stacks child layers properly for sticky header rows

The CL implements sticky section header rows in VPN page. Care is taken
to stack the rows with child controls that have layers below the sticky
section header rows.

BUG=664244
TEST=Run with --material-design-ink-drop-animation-speed=slow
     Touch a Wi-Fi connection row and while ripple is growing
     drag-scroll the list of connections up.
     Verify that the ripple is stacked below the Wi-Fi header row.

Review-Url: https://codereview.chromium.org/2557333003
Cr-Commit-Position: refs/heads/master@{#438689}
(cherry picked from commit cd9913053dc56f12271b0c73558635ffbc26c580)
==========

to

==========
[ash-md] Stacks child layers properly for sticky header rows

The CL implements sticky section header rows in VPN page. Care is taken
to stack the rows with child controls that have layers below the sticky
section header rows.

BUG=664244
TEST=Run with --material-design-ink-drop-animation-speed=slow
     Touch a Wi-Fi connection row and while ripple is growing
     drag-scroll the list of connections up.
     Verify that the ripple is stacked below the Wi-Fi header row.

Review-Url: https://codereview.chromium.org/2557333003
Cr-Commit-Position: refs/heads/master@{#438689}
(cherry picked from commit cd9913053dc56f12271b0c73558635ffbc26c580)

Committed:
https://chromium.googlesource.com/chromium/src/+/7000b78c4fb63b02f48700904b8f...
==========

[bruthig, 2016-12-22 22:29:23]

Committed patchset #1 (id:1) manually as
7000b78c4fb63b02f48700904b8f6c44f828322c.