Moving the release of moderate bindings to a listener.

Adding a new method to the ChildConnectionAllocator.Listener to notify
when a connection is added and making the ChildProcessLauncherHelper
use it to release the moderate bindings.
This is an intermediary step in changing the SpareChildConnection to
take an ChildConnectionAllocator instead of delegating the connection
creation to the ChildProcessLauncherHelper.

Bug: 702316
Change-Id: I6bfec0fd5df5a2420b26737115fd872585211d9f
Reviewed-on: https://chromium-review.googlesource.com/546921
Commit-Queue: Jay Civelli <jcivelli@chromium.org>
Reviewed-by: Jay Civelli <jcivelli@chromium.org>
Reviewed-by: Bo Liu <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#482526}
3 files changed