tree f558facf26172f611a48ff14dda1cdb13fec2633
parent 5b9a0a0e4d2cde254f43bcf39b7b39daa0e4d51f
author schenney@chromium.org <schenney@chromium.org> 1436387906 +0000
committer schenney@chromium.org <schenney@chromium.org> 1436387906 +0000

Avoid clearing pointers on layers still in the mapping's vector of layers.

When adjusting layers, a particular layer may be added to a grouped
mapping at a location earlier than where it already appears in the
layer vector. When we then clear the unused entries in the list, we
remove the layer and null its group mapping, despite it still being
present earlier in the vector.

R=vollick
BUG=507988

Review URL: https://codereview.chromium.org/1227763002

git-svn-id: svn://svn.chromium.org/blink/trunk@198534 bbb929c8-8fbe-4397-9dbb-9b2b20218538