cc: Prevent ResourceUpdateContoller from uploading textures after lost context

cc: Prevent ResourceUpdateContoller from uploading textures after lost context

If the context was lost in the middle of the ResourceUpdateController
uploading textures, it would previously continue uploading textures.

ResourceUpdateController now stops uploading immediately and notifies
its client that the uploads have completed, which will allow the
commit to complete.

The LayerTreeHostContextTestLostContextWhileUpdatingResources unit
test now relys on the first draw to trigger the end of the test.
Relying on the first commit to end the test was incorrect before
this patch and would be incorrect after this patch, since losing the
context doesn't prevent the commit from finishing. Previously, the
end of the test was racing with the expected number of times the
context would be lost.

In order to rely on the first draw to end the test, SingleThreadProxy
now checks for lost context before drawing.

BUG=313790
TBR=danakj

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=238178

[commit-bot: I haz the power, 2013-12-02 17:39:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/reveman@chromium.org/99553002/1

[commit-bot: I haz the power, 2013-12-02 20:52:22]

Change committed as 238178