Revert of Expose events in workers as per latest DOM specification (https://codereview.chromium.org/262173006/)

Reason for revert:
This may be causing issues with thread safety. I am reverting until I get a chance to investigate.

Original issue's description:
> Expose events in workers as per latest DOM specification
> 
> Expose events in workers as per latest DOM specification:
> https://github.com/whatwg/dom/commit/0f69e7175dcae9edffa636bb213991330d225bf3
> 
> This CL exposes Event, CustomEvent and EventTarget to Workers and not only
> in the primary global scope (Window), as per the latest DOM specification.
> 
> Firefox 29 exposes both Event and EventTarget to workers but not CustomEvent
> (known bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1003432).
> IE11 exposes Event only to workers.
> 
> R=arv@chromium.org, tkent@chromium.org
> BUG=370011
> TEST=webexposed/global-constructors-listing-dedicated-worker.html
> TEST=webexposed/global-constructors-listing-shared-worker.html
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=173328

TBR=arv@chromium.org,tkent@chromium.org,eseidel@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=370011

Review URL: https://codereview.chromium.org/267363003

git-svn-id: svn://svn.chromium.org/blink/trunk@173525 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Oilpan: Use transition types for VTTCue and VTTElement.

R=haraken@chromium.org
BUG=357163

Review URL: https://codereview.chromium.org/270313002

git-svn-id: svn://svn.chromium.org/blink/trunk@173526 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add diagnostic code in order to investigate a time format issue.

Add "datetimeformat" attribute to a shadow element for a detected date/time
format. This attribute is visible only in DevTools.

BUG=370498

Review URL: https://codereview.chromium.org/270633002

git-svn-id: svn://svn.chromium.org/blink/trunk@173529 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Dispatch change event for input type=checkbox when checked but value is null

Checkbox dispatches change event when checked and dispatch event is not
based on value being null or not.

BUG=366989
R=tkent,keishi1
Test=If value attribute is null, when checkbox is checked a change event
is triggered.

Review URL: https://codereview.chromium.org/255163002

git-svn-id: svn://svn.chromium.org/blink/trunk@173530 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[New Multicolumn] Make fast/multicol/overflow-content.html pass in the new implementation.

Insert a break at end of content on our own in the multicol code, to make sure
that overflow is properly accounted for.

BUG=369954

Review URL: https://codereview.chromium.org/263083009

git-svn-id: svn://svn.chromium.org/blink/trunk@173531 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Use WebScreenInfo for window.orientation.

Using WebScreenInfo in window.orientation will allow having a valid
value at any time, even when the renderer process just got created
because WebScreenInfo is passed at creation time.

Furthermore, it removes the need to pass the orientation value when
notifying Blink that a screen orientation happened.

BUG=154478

Review URL: https://codereview.chromium.org/267423002

git-svn-id: svn://svn.chromium.org/blink/trunk@173532 bbb929c8-8fbe-4397-9dbb-9b2b20218538