Switch BindingSet to Receiver

There should only be one mojom::GpuService message pipe so
GpuServiceImpl only needs one receiver instead of a set of them.

Bug: none
Change-Id: I76737d92dfcd4af84120709f4a25497ca34ab9e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1869396Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707452}

components/viz/service/gl/gpu_service_impl.cc

@@ -131,12 +131,6 @@ base::OnceCallback<void(Params&&...)> WrapCallback(
       base::RetainedRef(std::move(runner)), std::move(callback));
 }
 
-void DestroyBinding(mojo::BindingSet<mojom::GpuService>* binding,
-                    base::WaitableEvent* wait) {
-  binding->CloseAllBindings();
-  wait->Signal();
-}
-
 }  // namespace
 
 GpuServiceImpl::GpuServiceImpl(
@@ -163,8 +157,7 @@ GpuServiceImpl::GpuServiceImpl(
 #if BUILDFLAG(ENABLE_VULKAN)
       vulkan_implementation_(vulkan_implementation),
 #endif
-      exit_callback_(std::move(exit_callback)),
-      bindings_(std::make_unique<mojo::BindingSet<mojom::GpuService>>()) {
+      exit_callback_(std::move(exit_callback)) {
   DCHECK(!io_runner_->BelongsToCurrentThread());
   DCHECK(exit_callback_);
 
@@ -214,11 +207,18 @@ GpuServiceImpl::~GpuServiceImpl() {
   bind_task_tracker_.TryCancelAll();
   logging::SetLogMessageHandler(nullptr);
   g_log_callback.Get().Reset();
+
+  // Destroy the receiver on the IO thread.
   base::WaitableEvent wait;
-  if (io_runner_->PostTask(
-          FROM_HERE, base::BindOnce(&DestroyBinding, bindings_.get(), &wait))) {
+  auto destroy_receiver_task = base::BindOnce(
+      [](mojo::Receiver<mojom::GpuService>* receiver,
+         base::WaitableEvent* wait) {
+        receiver->reset();
+        wait->Signal();
+      },
+      &receiver_, &wait);
+  if (io_runner_->PostTask(FROM_HERE, std::move(destroy_receiver_task)))
     wait.Wait();
-  }
 
   if (watchdog_thread_)
     watchdog_thread_->OnGpuProcessTearDown();
@@ -338,15 +338,17 @@ void GpuServiceImpl::InitializeWithHost(
     watchdog_thread()->AddPowerObserver();
 }
 
-void GpuServiceImpl::Bind(mojom::GpuServiceRequest request) {
+void GpuServiceImpl::Bind(
+    mojo::PendingReceiver<mojom::GpuService> pending_receiver) {
   if (main_runner_->BelongsToCurrentThread()) {
     bind_task_tracker_.PostTask(
         io_runner_.get(), FROM_HERE,
         base::BindOnce(&GpuServiceImpl::Bind, base::Unretained(this),
-                       std::move(request)));
+                       std::move(pending_receiver)));
     return;
   }
-  bindings_->AddBinding(this, std::move(request));
+  DCHECK(!receiver_.is_bound());
+  receiver_.Bind(std::move(pending_receiver));
 }
 
 void GpuServiceImpl::DisableGpuCompositing() {
@@ -732,7 +734,7 @@ void GpuServiceImpl::EstablishGpuChannel(int32_t client_id,
     if (IsExiting()) {
       // We are already exiting so there is no point in responding. Close the
       // receiver so we can safely drop the callback.
-      bindings_->CloseAllBindings();
+      receiver_.reset();
       return;
     }
 

components/viz/service/gl/gpu_service_impl.h

@@ -32,7 +32,8 @@
 #include "gpu/ipc/service/gpu_config.h"
 #include "gpu/ipc/service/x_util.h"
 #include "gpu/vulkan/buildflags.h"
-#include "mojo/public/cpp/bindings/binding_set.h"
+#include "mojo/public/cpp/bindings/pending_receiver.h"
+#include "mojo/public/cpp/bindings/receiver.h"
 #include "mojo/public/cpp/bindings/remote.h"
 #include "mojo/public/cpp/bindings/shared_remote.h"
 #include "services/viz/privileged/mojom/gl/gpu_host.mojom.h"
@@ -98,7 +99,7 @@ class VIZ_SERVICE_EXPORT GpuServiceImpl : public gpu::GpuChannelManagerDelegate,
       gpu::SyncPointManager* sync_point_manager = nullptr,
       gpu::SharedImageManager* shared_image_manager = nullptr,
       base::WaitableEvent* shutdown_event = nullptr);
-  void Bind(mojom::GpuServiceRequest request);
+  void Bind(mojo::PendingReceiver<mojom::GpuService> pending_receiver);
 
   scoped_refptr<gpu::SharedContextState> GetContextState();
 
@@ -358,9 +359,10 @@ class VIZ_SERVICE_EXPORT GpuServiceImpl : public gpu::GpuChannelManagerDelegate,
 
   base::Time start_time_;
 
-  // Used to track the task to bind a GpuServiceRequest on the io thread.
+  // Used to track the task to bind |receiver_| on the IO thread.
   base::CancelableTaskTracker bind_task_tracker_;
-  std::unique_ptr<mojo::BindingSet<mojom::GpuService>> bindings_;
+  // Should only be accessed on the IO thread after creation.
+  mojo::Receiver<mojom::GpuService> receiver_{this};
 
 #if defined(OS_WIN)
   // Used to track if the Dx Diag task on a different thread is still running.