Revert of Delay filesystem API async callbacks while JS debugger is on pause. (https://codereview.chromium.org/303523002/)

Reason for revert:
Broke Oilpan compile http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Oilpan/builds/5165

Original issue's description:
> Delay filesystem API async callbacks while JS debugger is on pause.
> 
> While the Javascript VM is paused all callbacks into the javascipt from C++ bindings are ignored.
> For async filesystem API callbacks we can postpone the callbacks while debugger is on pause, rather than just ignore them.
> 
> BUG=370100
> R=kinuko@chromium.org, nhiroki@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=174865

TBR=kinuko@chromium.org,nhiroki@chromium.org,yurys@chromium.org,aandrey@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=370100

Review URL: https://codereview.chromium.org/301543006

git-svn-id: svn://svn.chromium.org/blink/trunk@174869 bbb929c8-8fbe-4397-9dbb-9b2b20218538