gpu: Have GpuService create and own GpuMemoryBufferFactory.

services/ui/ws/gpu_host_unittest.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "services/ui/ws/gpu_host.h"
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 35 matching lines @@
  public:
   TestGpuService();
   ~TestGpuService() override {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TestGpuService);
 };
 
 TestGpuService::TestGpuService()
     : GpuService(gpu::GPUInfo(),
-                 nullptr,
-                 nullptr,
+                 nullptr /* watchdog_thread */,
                  base::ThreadTaskRunnerHandle::Get(),
                  gpu::GpuFeatureInfo()) {}
 
 }  // namespace
 
 class GpuHostTest : public testing::Test {
  public:
   GpuHostTest() {}
   ~GpuHostTest() override {}
 
@@ skipping 43 matching lines @@
 TEST_F(GpuHostTest, GpuClientDestructionOrder) {
   base::WeakPtr<GpuClient> client_ref = AddGpuClient();
   EXPECT_NE(nullptr, client_ref);
   DestroyHost();
   EXPECT_EQ(nullptr, client_ref);
 }
 
 }  // namespace test
 }  // namespace ws
 }  // namespace ui