[Loader] Add thread-safety assertions to WorkerLoaderClientBridgeSyncHelper
After 515850 was fixed, no ThreadableLoaderClient methods will be called when
|m_done| is true. RELEASE_ASSERT is used because assertion failure might
|result in use-after-free.
BUG=421627, 515850
TEST=
http/tests/xmlhttprequest/workers/shared-worker-access-control-basic-get-fail-non-simple.html
http/tests/xmlhttprequest/workers/access-control-basic-get-fail-non-simple.html
Review URL: https://codereview.chromium.org/1250373005
git-svn-id: svn://svn.chromium.org/blink/trunk@202573 bbb929c8-8fbe-4397-9dbb-9b2b20218538
2 files changed
