GitLab

Reason for revert:
This looks like the most likely culprit for the crash in http://build.chromium.org/p/chromium.linux/builders/Linux%20Tests%20%28dbg%29%281%29/builds/32814.

Partial stack dump:
	[16752:16752:0807/140640:WARNING:password_store_factory.cc(215)] Using basic (unencrypted) store for password storage. See http://code.google.com/p/chromium/wiki/LinuxPasswordStorage for more information about password storage options.
	[16783:16783:0807/140640:ERROR:sandbox_linux.cc(304)] InitializeSandbox() called with multiple threads in process gpu-process
	[16783:16783:0807/140640:WARNING:x11_util.cc(1408)] X error received: serial 61, error_code 8 (BadMatch (invalid parameter attributes)), request_code 72, minor_code 0 (X_PutImage)
	ASSERTION FAILED: info.fAlphaType == m_imageInfo.fAlphaType
	../../third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.cpp(78) : virtual bool blink::DecodingImageGenerator::onGetPixels(const SkImageInfo &, void *, size_t, SkPMColor *, int *)
	1   0x7f11fbdbcdd8
	2   0x7f11fb0ea18c SkImageGenerator::getPixels(SkImageInfo const&, void*, unsigned long, unsigned int*, int*)
	3   0x7f11fb0bc349
	4   0x7f11fb13e30b SkPixelRef::lockPixels(SkPixelRef::LockRec*)
	5   0x7f11fb13e479 SkPixelRef::lockPixels()
	6   0x7f11fb04a6ea SkBitmap::lockPixels() const
	7   0x7f11fb05032d
	8   0x7f11fb0c35ca
	9   0x7f11fb051f51 SkBitmapDevice::drawBitmap(SkDraw const&, SkBitmap const&, SkMatrix const&, SkPaint const&)
	10  0x7f11fb05223b SkBitmapDevice::drawBitmapRect(SkDraw const&, SkBitmap const&, SkRect const*, SkRect const&, SkPaint const&, SkCanvas::DrawBitmapRectFlags)
	11  0x7f11fb0a3d4a SkCanvas::internalDrawBitmapRect(SkBitmap const&, SkRect const*, SkRect const&, SkPaint const*, SkCanvas::DrawBitmapRectFlags)
	12  0x7f11fb0a3de1 SkCanvas::drawBitmapRectToRect(SkBitmap const&, SkRect const*, SkRect const&, SkPaint const*, SkCanvas::DrawBitmapRectFlags)
	13  0x7f11fb12c296
	14  0x7f11fb12b9e1
	15  0x7f11fb12241f SkPicture::draw(SkCanvas*, SkDrawPictureCallback*) const
	16  0x7f11fc67a2a7 cc::Picture::Raster(SkCanvas*, SkDrawPictureCallback*, cc::Region const&, float)
	17  0x7f11fc6adc59 cc::PicturePileImpl::RasterCommon(SkCanvas*, SkDrawPictureCallback*, gfx::Rect const&, float, cc::RenderingStatsInstrumentation*, bool)
	18  0x7f11fc6ae45e cc::PicturePileImpl::RasterToBitmap(SkCanvas*, gfx::Rect const&, float, cc::RenderingStatsInstrumentation*)

Original issue's description:
> Define SK_PICTURE_CLONE_NOOP.
> 
> This makes SkPicture::clone() a cheap ref, meaning impl-side painting will render
> tiles concurrently from the same source SkPicture rather than from clones.
> 
> After testing for a few months in Skia, we believe SkPicture is thread safe enough
> to try this out on the Chrome bots.  Please revert this at the slightest sign of
> crash, flaky drawing, etc.
> 
> CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:linux_layout_rel
> 
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288096

TBR=reed@google.com,robertphillips@google.com,mtklein@google.com,mtklein@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/455463002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288190 0039d316-1c4b-4281-b951-d872f2087c98