Revert of Oilpan: Move StyleSheets to the oilpan heap using RefCountedGarbageCollected. (https://codereview.chromium.org/173783002/)

Reason for revert:
fast/dom/shadow/move-style-scoped-to-another-shadowroot-crash.html is crashing

Original issue's description:
> Oilpan: Move StyleSheets to the oilpan heap using RefCountedGarbageCollected.
> 
> Resolve CSSStyleSheet/StyleSheetContents finalization order issue
> by making the client pointers in StyleSheetContents weak. That
> involves going to a hash set instead of a vector and therefore
> we need a hash function for RawPtr.
> 
> The style engine change is in preparation for tracing the contained
> collections of CSSStyleSheet pointers.
> 
> R=haraken@chromium.org, jochen@chromium.org, vegorov@chromium.org
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168030

TBR=haraken@chromium.org,jochen@chromium.org,vegorov@chromium.org,erik.corry@gmail.com,mikhail.pozdnyakov@intel.com,ager@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/178403003

git-svn-id: svn://svn.chromium.org/blink/trunk@168038 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Web Animations CSS: Dispatch all animation events in the animation frame.

Previously only events generated during the first timing update for a frame
were fired here and the dispatch mechanism was separate from the
ScriptedAnimationController.

Review URL: https://codereview.chromium.org/177203009

git-svn-id: svn://svn.chromium.org/blink/trunk@168039 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Get rid of PageGroup

The page group is a leftover concept from WebKit.

We now have a new getter for ordinary pages (all pages, including
special ones as SVG, inspector overlay etc can be accessed already).

BUG=288249

Review URL: https://codereview.chromium.org/180983003

git-svn-id: svn://svn.chromium.org/blink/trunk@168040 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Use SkLayerDrawLooper::Builder to construct SkLayerDrawLooper.

The addLayer() methods of SkLayerDrawLooper will soon be removed. This CL
updates all uses of those methods with the corresponding methods in
SkLayerDrawLooper::Builder.

BUG=skia:2141

Review URL: https://codereview.chromium.org/177473003

git-svn-id: svn://svn.chromium.org/blink/trunk@168041 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert of Revert of Turn window.postMessage into an ActiveDOMObject (https://codereview.chromium.org/183293002/)

Reason for revert:
This was not the culprit for the LayoutTest crashes

Original issue's description:
> Revert of Turn window.postMessage into an ActiveDOMObject (https://codereview.chromium.org/157243003/)
> 
> Reason for revert:
> A tentative cause for crashes of
> fast/dom/custom/document-register-reentrant-throwing-constructor.html,
> fast/events/before-unload-return-bad-value.html,
> fast/events/onerror-no-constructor.html
> 
> Original issue's description:
> > Turn window.postMessage into an ActiveDOMObject
> > 
> > When JavaScript execution is paused by the debugger messages sent via postMessage should be suspended similar to other events.
> > 
> > BUG=224874
> > 
> > Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168026
> 
> TBR=pfeldman@chromium.org,aandrey@chromium.org,abarth@chromium.org,atwilson@chromium.org,yurys@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=224874
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168036

TBR=pfeldman@chromium.org,aandrey@chromium.org,abarth@chromium.org,atwilson@chromium.org,yurys@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=224874

Review URL: https://codereview.chromium.org/183093004

git-svn-id: svn://svn.chromium.org/blink/trunk@168042 bbb929c8-8fbe-4397-9dbb-9b2b20218538