gpu: Replace GpuMsg_Finalize ipc with equivalent mojom api

content/browser/gpu/gpu_process_host.cc

Index: content/browser/gpu/gpu_process_host.cc
diff --git a/content/browser/gpu/gpu_process_host.cc b/content/browser/gpu/gpu_process_host.cc
index 33dc88f7ca9cff248d0d8a66fa1fa49fb5db53f8..e2328dbbac1b844b0ffe6f0fe630289b8bb7bd41 100644
--- a/content/browser/gpu/gpu_process_host.cc
+++ b/content/browser/gpu/gpu_process_host.cc
@@ -200,8 +200,7 @@ void RunCallbackOnIO(GpuProcessHost::GpuProcessKind kind,
                      bool force_create,
                      const base::Callback<void(GpuProcessHost*)>& callback) {
   GpuProcessHost* host = GpuProcessHost::Get(kind, force_create);
-  if (host)
-    callback.Run(host);
+  callback.Run(host);
 }
 
 #if defined(USE_OZONE)
@@ -988,10 +987,6 @@ void GpuProcessHost::ForceShutdown() {
   process_->ForceShutdown();
 }
 
-void GpuProcessHost::StopGpuProcess() {
-  Send(new GpuMsg_Finalize());
-}
-
 bool GpuProcessHost::LaunchGpuProcess(gpu::GpuPreferences* gpu_preferences) {
   const base::CommandLine& browser_command_line =
       *base::CommandLine::ForCurrentProcess();