Peer::initialize() should wake up a worker thread after initializing Bridge::m_peer

This is another fix for threading issues of WebSocket in oilpan builds.

Currently Peer::initialize() wakes up a worker thread before initializing Bridge::m_peer. Thus the following scenario can happen:

(1) Bridge::m_peer is initialized to 0.
(2) Bridge::initialize() is called in the worker thread.
(3) Peer::initialize() is called in the main thread.
(4) Peer::initialize() wakes up the worker thread before setting Bridge::m_peer.
(5) A shutdown event is sent to the worker thread.
(6) The worker thread calls Bridge::destroy().
(7) Bridge::destroy() calls Peer::destroy() using the Bridge::m_peer that is not yet initialized.

This will hopefully fix flaky crashes of worker-reload.html and worker-reload-repeated.html in oilpan builds:

http://test-results.appspot.com/dashboards/flakiness_dashboard.html#group=%40ToT%20Blink&tests=http%2Ftests%2Fwebsocket%2Fworkers%2Fworker-reload-repeated.html%2Chttp%2Ftests%2Fwebsocket%2Fworkers%2Fworker-reload.html

Review URL: https://codereview.chromium.org/347933004

git-svn-id: svn://svn.chromium.org/blink/trunk@176911 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Prevent leak of target after its removing.

BUG=

Review URL: https://codereview.chromium.org/345183004

git-svn-id: svn://svn.chromium.org/blink/trunk@176912 bbb929c8-8fbe-4397-9dbb-9b2b20218538