Don't leak image in Surface test.

Don't leak image in Surface test.

==7023== 5,056 (896 direct, 4,160 indirect) bytes in 8 blocks are definitely lost in loss record 947 of 2,656
==7023==    at 0x4C2B1C7: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7023==    by 0x82CB99: SkNewImageFromBitmapTexture(SkBitmap const&, int, SkSurface::Budgeted) (SkImage_Gpu.cpp:64)
==7023==    by 0x81A1CF: SkSurface_Gpu::onNewImageSnapshot(SkSurface::Budgeted) (SkSurface_Gpu.cpp:50)
==7023==    by 0x694F9D: SkSurface::newImageSnapshot(SkSurface::Budgeted) (SkSurface_Base.h:92)
==7023==    by 0x55EA7C: test_Surface(skiatest::Reporter*, GrContextFactory*) (SurfaceTest.cpp:485)
==7023==    by 0x407CB2: run_test(skiatest::Test*) (DM.cpp:399)
==7023==    by 0x408382: run_enclave_and_gpu_tests(SkTArray<Task, false>*) (DM.cpp:411)
==7023==    by 0x68B71E: SkTaskGroup::wait() (SkTaskGroup.cpp:67)
==7023==    by 0x40934E: dm_main() (DM.cpp:455)
==7023==    by 0x409483: main (DM.cpp:477)

http://build.chromium.org/p/client.skia/builders/Test-Ubuntu12-ShuttleA-GTX550Ti-x86_64-Release-Valgrind/builds/276/steps/dm/logs/stdio

TBR=bsalomon@google.com

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/31ff29829e3ceb8f5af0a655285d83abb6662c85

[mtklein, 2015-01-24 19:18:54]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-01-24 19:19:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/872183002/1

[commit-bot: I haz the power, 2015-01-24 19:27:30]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/31ff29829e3ceb8f5af0a655285d83abb6662c85

[tfarina, 2015-01-24 22:03:10]

tfarina@chromium.org changed reviewers:
+ tfarina@chromium.org

[tfarina, 2015-01-24 22:03:11]

https://codereview.chromium.org/872183002/diff/1/tests/SurfaceTest.cpp
File tests/SurfaceTest.cpp (right):

https://codereview.chromium.org/872183002/diff/1/tests/SurfaceTest.cpp#newcod...
tests/SurfaceTest.cpp:485: SkAutoTUnref<SkImage>
image(surface->newImageSnapshot(ibudgeted));
lgtm