Add a flag to flush the canvases during SkMultiPictureDraw::draw().

Add a flag to flush the canvases during SkMultiPictureDraw::draw().

This is necessary for multisampling, so that each multisampled render
target resolves before Chrome's compositor attempts to draw the
texture.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/772604c214e8c12ee16d2eb60f4b7acbcdd2129e

[Stephen White, 2015-01-27 18:54:14]

senorblanco@chromium.org changed reviewers:
+ bsalomon@google.com, robertphillips@google.com

[Stephen White, 2015-01-27 18:54:39]

PTAL.

[bsalomon, 2015-01-27 20:24:59]

On 2015/01/27 18:54:39, Stephen White wrote:
> PTAL.

where does the resolve happen? Do we do that in SkGpuDevice?

[Stephen White, 2015-01-27 20:28:34]

On 2015/01/27 20:24:59, bsalomon wrote:
> On 2015/01/27 18:54:39, Stephen White wrote:
> > PTAL.
> 
> where does the resolve happen? Do we do that in SkGpuDevice?

SkGpuDevice::flush() calls fRenderTarget->prepareForExternalRead().

[Stephen White, 2015-01-27 20:30:30]

On 2015/01/27 20:28:34, Stephen White wrote:
> On 2015/01/27 20:24:59, bsalomon wrote:
> > On 2015/01/27 18:54:39, Stephen White wrote:
> > > PTAL.
> > 
> > where does the resolve happen? Do we do that in SkGpuDevice?
> 
> SkGpuDevice::flush() calls fRenderTarget->prepareForExternalRead().

(which calls GrContext::prepareSurfaceForExternalRead(this), which calls
GrGpu::resolveRenderTarget(rt).)

[bsalomon, 2015-01-28 14:39:30]

On 2015/01/27 20:30:30, Stephen White wrote:
> On 2015/01/27 20:28:34, Stephen White wrote:
> > On 2015/01/27 20:24:59, bsalomon wrote:
> > > On 2015/01/27 18:54:39, Stephen White wrote:
> > > > PTAL.
> > > 
> > > where does the resolve happen? Do we do that in SkGpuDevice?
> > 
> > SkGpuDevice::flush() calls fRenderTarget->prepareForExternalRead().
> 
> (which calls GrContext::prepareSurfaceForExternalRead(this), which calls
> GrGpu::resolveRenderTarget(rt).)

gotcha, lgtm

[Stephen White, 2015-01-28 15:42:43]

The CQ bit was checked by senorblanco@chromium.org

[commit-bot: I haz the power, 2015-01-28 15:43:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/878653004/1

[commit-bot: I haz the power, 2015-01-28 19:01:09]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/772604c214e8c12ee16d2eb60f4b7acbcdd2129e