content: implement unittests backend for Ozone GBM

ui/ozone/public/ozone_gpu_test_helper.cc

Index: ui/ozone/public/ozone_gpu_test_helper.cc
diff --git a/ui/ozone/public/ozone_gpu_test_helper.cc b/ui/ozone/public/ozone_gpu_test_helper.cc
index fe5a17b31cdb9775f7337863131e9ac4c3f14c02..81ef9c490297b2f1073872c00686b576e152a25e 100644
--- a/ui/ozone/public/ozone_gpu_test_helper.cc
+++ b/ui/ozone/public/ozone_gpu_test_helper.cc
@@ -4,6 +4,7 @@
 
 #include "ui/ozone/public/ozone_gpu_test_helper.h"
 
+#include "base/run_loop.h"
 #include "base/thread_task_runner_handle.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_message.h"
@@ -131,4 +132,32 @@ bool OzoneGpuTestHelper::Initialize(
   return true;
 }
 
+// static
+std::unique_ptr<OzoneInitializerForTest> OzoneInitializerForTest::Create() {
+  std::unique_ptr<OzoneInitializerForTest> self(new OzoneInitializerForTest());
+  if (!self->Initialize())
+    return nullptr;
+  return self;
+}
+
+OzoneInitializerForTest::OzoneInitializerForTest() {}
+
+OzoneInitializerForTest::~OzoneInitializerForTest() {}
+
+bool OzoneInitializerForTest::Initialize() {
+  OzonePlatform::InitializeForUI();
+  OzonePlatform::InitializeForGPU();
+  gpu_helper_.reset(new OzoneGpuTestHelper);
+  if (!gpu_helper_->Initialize(base::ThreadTaskRunnerHandle::Get(),
+                               base::ThreadTaskRunnerHandle::Get())) {
+    return false;
+  }
+  {
+    base::MessageLoop::ScopedNestableTaskAllower allow(
+        base::MessageLoop::current());
+    base::RunLoop().RunUntilIdle();
+  }
+  return true;
+}
+
 }  // namespace ui