Fix OzonePlatform initialization in VideoTestEnviroment

VideoTestEnviroment sets up ozone for ui and gpu in the same
process/thread. So, it should set InitParams::single_process to true.

BUG=998113
TEST=./video_decode_accelerator_tests on eve

Change-Id: Iad080267aa471c986721c471f2f5a1dd5b2f34d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1822662
Commit-Queue: Mohsen Izadi <mohsen@chromium.org>
Reviewed-by: David Staessens <dstaessens@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699574}

media/gpu/test/video_test_environment.cc

@@ -53,7 +53,7 @@ VideoTestEnvironment::VideoTestEnvironment() {
   LOG(WARNING) << "Initializing Ozone Platform...\n"
                   "If this hangs indefinitely please call 'stop ui' first!";
   ui::OzonePlatform::InitParams params;
-  params.single_process = false;
+  params.single_process = true;
   ui::OzonePlatform::InitializeForUI(params);
   ui::OzonePlatform::InitializeForGPU(params);
   ui::OzonePlatform::GetInstance()->AfterSandboxEntry();