Revert of Back PaintRecord with PaintOpBuffer instead of SkPicture (patchset #42 id:810001 of https://codereview.chromium.org/2768143002/ )

Reason for revert:
Reverting due to CrOS breakage.
crbug.com/712102

Original issue's description:
> Back PaintRecord with PaintOpBuffer instead of SkPicture
>
> Change the backing of PaintRecord to be a data structure implemented in
> cc/paint instead of using SkPicture directly.  This new class cribs heavily
> from SkLiteDL.
>
> PaintRecord used to be a typedef to an SkPicture but now is a typedef to
> a PaintOpBuffer.  (This leaves some flexibility to change this in the
> future to an interface without having to modify all of Chromium again.)
>
> PaintOpBuffer stores a contiguous array of ops, with the ops stored
> in place.  As an optimization, the first op is stored locally in the
> PaintOpBuffer itself to avoid extra allocations for small pictures.
>
> This patch moves slow path counting from a gpu analysis canvas into
> PaintOpBuffer directly.  As ops are recorded, slow paths are counted, and
> a PaintRecord now knows how many ops it has.  This is about a 1.5% savings
> for record time (gpu analysis was 2% and 0.5% overhead to record later).
>
> This patch also implements the SkRecordNoopSaveLayerDrawRestores
> optimization from Skia at raster time.  This takes save layer (just
> opacity) / draw / restore commands and turns them into draws with
> opacity.  It moves that optimization from Blink at record time inside of
> CompositingRecorder and moves it to both DisplayItemList::RasterItem
> and PaintOpBuffer::playback (since a save could be either a DisplayItem
> or a PaintOp).  It's not as robust as Skia's solution and so misses
> a few cases that Skia catches, but the rasterize and record on 10k
> page agreed that performance was good enough.
>
> CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
>
> Review-Url: https://codereview.chromium.org/2768143002
> Cr-Commit-Position: refs/heads/master@{#464809}
> Committed: https://chromium.googlesource.com/chromium/src/+/e49d70a44bf12043cc781390f7fc53ce7b4ac807

TBR=chrishtr@chromium.org,danakj@chromium.org,mtklein@chromium.org,thakis@chromium.org,vitalybuka@chromium.org,vmpstr@chromium.org,enne@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.

Review-Url: https://codereview.chromium.org/2820133005
Cr-Commit-Position: refs/heads/master@{#465196}