Revert of HTMLParser should use current value of scriptEnabled flag (https://codereview.chromium.org/313173012/)

Reason for revert:
This patch *appears* to break AwSettingsTest and
AwContentsClientShouldOverrideUrlLoadingTest:
http://build.chromium.org/p/chromium.webkit/builders/Android%20Tests%20(dbg)

This is my wild guess but it might be possible
that this patch is the cause, since the tests in
question call setJavaScriptEnabled(true).

Apologies if my guess is wrong. I'll revert the
revert if it turned out that I'm wrong.

Original issue's description:
> HTMLParser should use current value of scriptEnabled flag
> 
> This CL adds caching  of scriptEnabled setting to Document.
> 
> When page is reloaded we create new parser throught DocumentLoader::ensureWriter
> and set scriptEnabled flag. ContentSettingsObserver::allowScript method is
> responsible for checking settings but it uses cache. Cache is cleared on
> DidCommitProvisionalLoad but parser is already created before that. However we
> can't clear cache earlier because unload events for old page might be fired and
> it depends on old page settings (cached).
> 
> BUG=232410
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177664

NOTREECHECKS=true
NOTRY=true
BUG=232410

Review URL: https://codereview.chromium.org/375263002

git-svn-id: svn://svn.chromium.org/blink/trunk@177730 bbb929c8-8fbe-4397-9dbb-9b2b20218538