Update liftetime management of GpuClient

services/ui/ws/gpu_host.h

Index: services/ui/ws/gpu_host.h
diff --git a/services/ui/ws/gpu_host.h b/services/ui/ws/gpu_host.h
index b937266a5cc7136b079d451ae36d421b6797c376..d2302a39f7408ca6e90e289190b92ec9fab8ce54 100644
--- a/services/ui/ws/gpu_host.h
+++ b/services/ui/ws/gpu_host.h
@@ -12,6 +12,7 @@
 #include "gpu/ipc/client/gpu_channel_host.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "mojo/public/cpp/bindings/interface_request.h"
+#include "mojo/public/cpp/bindings/strong_binding_set.h"
 #include "services/ui/gpu/gpu_main.h"
 #include "services/ui/gpu/interfaces/gpu_host.mojom.h"
 #include "services/ui/gpu/interfaces/gpu_service.mojom.h"
@@ -23,6 +24,10 @@ class ServerGpuMemoryBufferManager;
 
 namespace ws {
 
+namespace test {
+class GpuHostTest;
+}  // namespace test
+
 class GpuHostDelegate;
 
 // Sets up connection from clients to the real service implementation in the GPU
@@ -32,7 +37,7 @@ class GpuHost : public mojom::GpuHost {
   explicit GpuHost(GpuHostDelegate* delegate);
   ~GpuHost() override;
 
-  void Add(mojom::GpuRequest request);
+  mojom::Gpu* Add(mojom::GpuRequest request);
 
   void OnAcceleratedWidgetAvailable(gfx::AcceleratedWidget widget);
   void OnAcceleratedWidgetDestroyed(gfx::AcceleratedWidget widget);
@@ -42,6 +47,8 @@ class GpuHost : public mojom::GpuHost {
                                cc::mojom::DisplayCompositorClientPtr client);
 
  private:
+  friend class test::GpuHostTest;
+
   void OnBadMessageFromGpu();
 
   // mojom::GpuHost:
@@ -72,6 +79,8 @@ class GpuHost : public mojom::GpuHost {
   // because that will live in another process soon.
   std::unique_ptr<GpuMain> gpu_main_impl_;
 
+  mojo::StrongBindingSet<mojom::Gpu> gpu_bindings_;
+
   DISALLOW_COPY_AND_ASSIGN(GpuHost);
 };