This is related to  http://crbug.com/753273 . We want to remove rendering in vda_unittest. To do that, we need to replace the thumbnail test case that verifies the decode output.

There are three options: (1) add a javascript test (2) use the existing telemetry_gpu_integration_test (3) change vda_unittest so thumbnail test case doesn't need rendering.
Kuang-che is interested in adding a javascript test. So we'll try (1) first.