ChannelMojo: Bind the channel TaskRunner to the right thread

In some cases ChannelMojo is constructed on a different thread
from the one used for IPC. Instead of capturing the channel's
IPC task runner at construction time, capture it on Connect(),
which is always called on the IPC thread.

BUG=597615
[email protected]

Review URL: https://codereview.chromium.org/1837433002

Cr-Commit-Position: refs/heads/master@{#383246}
1 file changed