Change where layer hoisting data is gathered

Change where layer hoisting data is gathered

This CL:
1) removes the EXPERIMENTAL_optimize on SkCanvas & SkDevice
2) moves the saveLayer gathering step to endRecording
3) Replaces GPUOptimize with SkRecordComputeLayers
4) Update bench_pictures & render_pictures to provide the new flag

#2 also necessitated moving the BBH computation (and record optimization) out of SkPicture's ctor (and into endRecording)

Committed: https://skia.googlesource.com/skia/+/81f71b6630a9b7398bf983689436cccdd8dd3ff7

[robertphillips, 2014-11-10 17:00:20]

robertphillips@google.com changed reviewers:
+ bsalomon@google.com

[bsalomon, 2014-11-10 18:49:23]

lgtm

[robertphillips, 2014-11-10 21:53:27]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2014-11-10 21:54:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/718443002/80001

[commit-bot: I haz the power, 2014-11-10 21:56:04]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-11-10 21:56:05]

Try jobs failed on following builders:
  Test-Ubuntu13.10-GCE-NoGPU-x86_64-Debug-Trybot on client.skia
(http://build.chromium.org/p/client.skia/builders/Test-Ubuntu13.10-GCE-NoGPU-x...)
  Build-Win-VS2013-x86-Debug-Trybot on client.skia.compile
(http://build.chromium.org/p/client.skia.compile/builders/Build-Win-VS2013-x86...)

[robertphillips, 2014-11-11 12:45:22]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2014-11-11 12:45:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/718443002/100001

[commit-bot: I haz the power, 2014-11-11 12:54:54]

Committed patchset #6 (id:100001) as
https://skia.googlesource.com/skia/+/81f71b6630a9b7398bf983689436cccdd8dd3ff7