cc: Add ScopedWriteLock classes for raster to GpuMemoryBuffer or using Ganesh.

cc: Add ScopedWriteLock classes for raster to GpuMemoryBuffer or using Ganesh.

The refactor will allow ResourceProvider to use GpuMemoryBuffer instances
directly and expose them to RasterWorkerPool implementations.

This change is useful on its own as it cleans up the RasterWorkerPool
code and makes implementations more consistent with BitmapRasterWorkerPool
used for software compositing. It reduces the public API of the
ResourceProvider class and eliminates the read lock fence API in favor of
handling that as part of the resource provider implementation instead.

BUG=418553
Committed: https://crrev.com/9fe3035db0b3993856ef57136c71105a6f99d3bc
Cr-Commit-Position: refs/heads/master@{#298716}

[reveman, 2014-10-07 14:36:16]

reveman@chromium.org changed reviewers:
+ danakj@chromium.org, piman@chromium.org, vmpstr@chromium.org

[reveman, 2014-10-07 14:36:17]

Some cleanup in preparation for my CHROMIUM_image refactor. The patch that
refactor CHROMIUM_image is pretty large so I'm hoping I can land this separately
instead of including it in that patch. I think this patch makes sense on its
own.

[reveman, 2014-10-07 20:00:02]

Here's the follow up refactor of CHROMIUM_image that moves map/unmap to the
worker threads:
https://codereview.chromium.org/634083002

This patch needs to land first but the follow up might be useful for context
when reviewing this change.

[piman, 2014-10-07 20:50:08]

LGTM, I think it's a nice simplification to the API

[vmpstr, 2014-10-08 15:46:09]

lgtm

[reveman, 2014-10-08 15:47:13]

The CQ bit was checked by reveman@chromium.org

[commit-bot: I haz the power, 2014-10-08 15:48:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/635733004/1

[commit-bot: I haz the power, 2014-10-08 15:52:19]

Committed patchset #1 (id:1) as 503a1e0881b348549346da976f84633e18da4769

[commit-bot: I haz the power, 2014-10-08 15:52:55]

Patchset 1 (id:??) landed as
https://crrev.com/9fe3035db0b3993856ef57136c71105a6f99d3bc
Cr-Commit-Position: refs/heads/master@{#298716}