Add trace method for NoopUnderlyingSource GC mixin.

Following http://crbug.com/444565, the GC plugin insists on there being
a trace() defined for declared mixin classes. Add such for
NoopUnderlyingSource.

R=haraken
BUG=446121

Review URL: https://codereview.chromium.org/896993002

git-svn-id: svn://svn.chromium.org/blink/trunk@189507 bbb929c8-8fbe-4397-9dbb-9b2b20218538
1 file changed
tree: 75dc580a326d746db3e30358789f36829cdc976e
  1. third_party/