gpu: Completely remove GpuProcessHostUIShim.

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 a08b088404ee6999008cc784d203b37f5b811cdb..9d9f48f2513c8173840c2f3c3483acb55e3b4873 100644
--- a/ui/ozone/public/ozone_gpu_test_helper.cc
+++ b/ui/ozone/public/ozone_gpu_test_helper.cc
@@ -87,12 +87,6 @@ class FakeGpuProcessHost {
         ->OnGpuProcessLaunched(kGpuProcessHostId, gpu_io_task_runner_, sender);
   }
 
-  void InitOnUI() {
-    ui::OzonePlatform::GetInstance()
-        ->GetGpuPlatformSupportHost()
-        ->OnChannelEstablished();
-  }
-
  private:
   scoped_refptr<base::SingleThreadTaskRunner> gpu_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> gpu_io_task_runner_;
@@ -124,7 +118,6 @@ bool OzoneGpuTestHelper::Initialize(
                             base::Unretained(fake_gpu_process_host_.get())));
   io_helper_thread_->FlushForTesting();
 
-  fake_gpu_process_host_->InitOnUI();
   return true;
 }