ThreadSafeRefCountedGarbageCollected should use makeKeepAlive

Similar to RefCountedGarbageCollected, ThreadSafeRefCountedGarbageCollected
should use a helper method to create a self-keep-alive handle.
This change is to make it easier to blacklist a bad cast detected in UBSan.

BUG=405345
NOTRY=true

Review URL: https://codereview.chromium.org/489353003

git-svn-id: svn://svn.chromium.org/blink/trunk@180756 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Reject ServiceWorker CacheStorage promises with DOMExceptions per spec.

First, CacheStorage.has() and CacheStorage.delete() were not returning
correctly per spec, which is fixed.

Secondly, error returns were raw strings, this CL updates them to be
DOMExceptions of the correct types. As well, the error code to
exception function is moved into the Cache object, foreshadowing the
need for such a function in the Cache itself.

R=jsbell@chromium.org,dominicc@chromium.org,falken@chromium.org
BUG=392621

Review URL: https://codereview.chromium.org/493133002

git-svn-id: svn://svn.chromium.org/blink/trunk@180757 bbb929c8-8fbe-4397-9dbb-9b2b20218538