Revert of Remove --enable-per-tile-painting and --ui-enable-per-tile-painting. (https://codereview.chromium.org/164183012/)

Reason for revert:
Breaks compositor_unittests on ChromeOS.

http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%281%29/builds/39630

LayerWithRealCompositorTest.Delegate (run #1):
[ RUN      ] LayerWithRealCompositorTest.Delegate
../../ui/compositor/layer_unittest.cc:527: Failure
Value of: l1->bounds().size()
  Actual: 8-byte object \u003C90-01 00-00 90-01 00-00>
Expected: delegate.paint_size()
Which is: 8-byte object \u003C00-00 00-00 00-00 00-00>
...

LayerWithRealCompositorTest.NoScaleCanvas (run #1):
[ RUN      ] LayerWithRealCompositorTest.NoScaleCanvas
../../ui/compositor/layer_unittest.cc:1311: Failure
Value of: l1_delegate.paint_size().ToString()
  Actual: "0x0"
Expected: "280x360"
[  FAILED  ] LayerWithRealCompositorTest.NoScaleCanvas (112 ms)
...

I can repro the failures on my dev box and revert this CL fixes the problem.

Original issue's description:
> Remove --enable-per-tile-painting and --ui-enable-per-tile-painting.
> 
> The ui flag is always true on ChromeOS and off elsewhere. The other is
> never on and we're not planning to turn it on.
> 
> R=piman
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=251538

TBR=piman@chromium.org,danakj@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/168423002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251553 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251553