Revert 168780 "Handle has_more correctly"

It causes a compilation error on Oilpan builds.

> Handle has_more correctly
> 
> Return callbacksId from WebFileSystem::readDirectory().
> Add WebFileSystem::waitForAdditionalResult().
> Rewrite DirectoryReader and DirectoryReaderSync.
> 
> BUG=347900
> TEST=run_webkit_tests.sh http/tests/filesystem/\*
> TEST=run_webkit_tests.sh http/tests/inspector/filesystem/\*
> 
> Review URL: https://codereview.chromium.org/178333009

TBR=hashimoto@chromium.org

Review URL: https://codereview.chromium.org/191943003

git-svn-id: svn://svn.chromium.org/blink/trunk@168786 bbb929c8-8fbe-4397-9dbb-9b2b20218538