gpu: Introduce GpuInit.

services/ui/ws/gpu_service_proxy.cc

Index: services/ui/ws/gpu_service_proxy.cc
diff --git a/services/ui/ws/gpu_service_proxy.cc b/services/ui/ws/gpu_service_proxy.cc
index d53028182aaf3631dd802a0b577640ac9aebb9ee..68331c1ec4f97b3288728e5073ae4d4a70ef517e 100644
--- a/services/ui/ws/gpu_service_proxy.cc
+++ b/services/ui/ws/gpu_service_proxy.cc
@@ -11,7 +11,6 @@
 #include "gpu/ipc/client/gpu_channel_host.h"
 #include "services/shell/public/cpp/connection.h"
 #include "services/ui/common/gpu_type_converters.h"
-#include "services/ui/gpu/gpu_service_internal.h"
 #include "services/ui/ws/gpu_service_proxy_delegate.h"
 #include "services/ui/ws/mus_gpu_memory_buffer_manager.h"
 
@@ -33,7 +32,7 @@ GpuServiceProxy::GpuServiceProxy(GpuServiceProxyDelegate* delegate)
                       base::WaitableEvent::InitialState::NOT_SIGNALED) {
   // TODO(sad): Once GPU process is split, this would look like:
   //   connector->ConnectToInterface("mojo:gpu", &gpu_service_);
-  GpuServiceInternal::GetInstance()->Add(GetProxy(&gpu_service_));
+  gpu_main_.Add(GetProxy(&gpu_service_));
   gpu_service_->Initialize(
       base::Bind(&GpuServiceProxy::OnInitialized, base::Unretained(this)));
 }
@@ -63,7 +62,7 @@ void GpuServiceProxy::OnInternalGpuChannelEstablished(
   CHECK(io_thread_->StartWithOptions(thread_options));
 
   gpu_memory_buffer_manager_.reset(new MusGpuMemoryBufferManager(
-      GpuServiceInternal::GetInstance(), kInternalGpuChannelClientId));
+      gpu_main_.gpu_service(), kInternalGpuChannelClientId));
   gpu_channel_ = gpu::GpuChannelHost::Create(
       this, kInternalGpuChannelClientId, gpu_info_,
       IPC::ChannelHandle(channel_handle.release()), &shutdown_event_,