Remove GPU relinquish resources infrastructure and stop GPU process.

ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc

Index: ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc
diff --git a/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc b/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc
index bdaa9be5a6f48cab981836454c92080939fa6ce7..2e3daf99403caf8ba66e188bfbc28117ec79ef27 100644
--- a/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc
+++ b/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc
@@ -311,11 +311,6 @@ void DrmGpuPlatformSupport::OnSetGammaRamp(
   display_manager_->SetGammaRamp(id, lut);
 }
 
-void DrmGpuPlatformSupport::RelinquishGpuResources(
-    const base::Closure& callback) {
-  callback.Run();
-}
-
 void DrmGpuPlatformSupport::OnGetHDCPState(int64_t display_id) {
   HDCPState state = HDCP_STATE_UNDESIRED;
   bool success = display_manager_->GetHDCPState(display_id, &state);