Changes GpuServiceInternal from Binding to BindingSet

StrongBinding means GpuServiceInternal is deleted when the pipe is
closed, defeating the singleton nature. By converting to Binding when the pipe is closed GpuServiceInternal is not deleted.

BUG=none
TEST=none
R=sadrul@chromium.org

Review-Url: https://codereview.chromium.org/2302523002
Cr-Commit-Position: refs/heads/master@{#415763}

services/ui/gpu/gpu_service_internal.cc

@@ -63,6 +63,7 @@ GpuServiceInternal::~GpuServiceInternal() {
 }
 
 void GpuServiceInternal::Add(mojom::GpuServiceInternalRequest request) {
+  binding_.Close();
   binding_.Bind(std::move(request));
 }
 

services/ui/gpu/gpu_service_internal.h

@@ -18,7 +18,7 @@
 #include "gpu/ipc/service/gpu_channel_manager_delegate.h"
 #include "gpu/ipc/service/gpu_config.h"
 #include "gpu/ipc/service/x_util.h"
-#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "mojo/public/cpp/bindings/binding.h"
 #include "services/ui/gpu/interfaces/gpu_service_internal.mojom.h"
 #include "ui/gfx/native_widget_types.h"
 
@@ -153,7 +153,7 @@ class GpuServiceInternal : public gpu::GpuChannelManagerDelegate,
   // Information about the GPU, such as device and vendor ID.
   gpu::GPUInfo gpu_info_;
 
-  mojo::StrongBinding<mojom::GpuServiceInternal> binding_;
+  mojo::Binding<mojom::GpuServiceInternal> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuServiceInternal);
 };