Revert "Add [WillBeGarbageCollected] to Event.idl"

This CL caused a lot of failures in oilpan bots:
http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Oilpan/builds/1657

NOTRY=true

Review URL: https://codereview.chromium.org/185393006

git-svn-id: svn://svn.chromium.org/blink/trunk@168305 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[Promise] Avoid crash in stack exhausted circumstance.

Some operations such as createClosure and v8::ObjectTemplate::NewInstance
returns an empty handle when the stack is exhausted.
Promise should throw a StackOverFlow exception in such a case.

BUG=345088
R=haraken

Review URL: https://codereview.chromium.org/174073009

git-svn-id: svn://svn.chromium.org/blink/trunk@168306 bbb929c8-8fbe-4397-9dbb-9b2b20218538