Expose functionality to purge the GPU texture cache while running SampleApp.

Expose functionality to purge the GPU texture cache while running SampleApp.

Press 'p' to purge the cache.  A summary of the number of bytes of video memory
released is output to the command prompt.
Committed: https://code.google.com/p/skia/source/detail?r=3097

[twiz, 2012-01-27 17:49:14]

PTAL.

I believe my emacs settings remove empty lines on the end of files.  Let me know
if I need to re-add the lines to the header files.

[bsalomon, 2012-01-27 18:02:22]

LGTM.

Just a note about how scratch textures work: When a client locks a scratch
texture it is detached from cache. This so that no one else gets the same one.
It's bytes won't be freed when purgeAllGpuResources() is called and your
function would count its bytes (so it won't return zero). Once the client lets
go of the scratch it'll be reattached. If at that point the cache budget is less
than the size of the scratch then the scratch will be freed.

https://codereview.appspot.com/5587045/diff/1/include/gpu/GrContext.h
File include/gpu/GrContext.h (right):

https://codereview.appspot.com/5587045/diff/1/include/gpu/GrContext.h#newcode81
include/gpu/GrContext.h:81: size_t getGPUTextureCacheBytes() const;
nit: It may be at odds with the rest of skia, but Ganesh uses "Gpu" rather than
"GPU" everywhere else. Perhaps we should change to be like Skia but I'd rather
do it all at once rather than piecemeal.

[twiz, 2012-01-27 18:58:14]

https://codereview.appspot.com/5587045/diff/1/include/gpu/GrContext.h
File include/gpu/GrContext.h (right):

https://codereview.appspot.com/5587045/diff/1/include/gpu/GrContext.h#newcode81
include/gpu/GrContext.h:81: size_t getGPUTextureCacheBytes() const;
On 2012/01/27 18:02:22, bsalomon wrote:
> nit: It may be at odds with the rest of skia, but Ganesh uses "Gpu" rather
than
> "GPU" everywhere else. Perhaps we should change to be like Skia but I'd rather
> do it all at once rather than piecemeal.

Done.

[junov1, 2012-01-27 19:18:58]

Why not tear down the entire GrContext?  There is other state in there that
might be worth resetting on demand.