gpu: Make the mus-gpu client-lib test-friendly.

services/ui/public/cpp/tests/gpu_unittest.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "services/ui/public/cpp/gpu/gpu.h"
+
+#include "base/callback_helpers.h"
+#include "base/test/scoped_task_environment.h"
+#include "gpu/config/gpu_info.h"
+#include "mojo/public/cpp/bindings/binding_set.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace ui {
+
+namespace {
+
+class TestGpuImpl : public mojom::Gpu {
+ public:
+  TestGpuImpl() {}
+  ~TestGpuImpl() override {}
+
+  mojom::GpuPtr GetPtr() {
+    mojom::GpuPtr ptr;
+    bindings_.AddBinding(this, mojo::MakeRequest(&ptr));
+    return ptr;
+  }
+
+  void WaitUntilChannelRequest() {
+    DCHECK(quit_closure_.is_null());
+    base::RunLoop run_loop;
+    quit_closure_ = run_loop.QuitClosure();
+    run_loop.Run();
+    quit_closure_ = base::Closure();
+  }
+
+  bool RespondToGpuChannelRequests() {
+    if (establish_channel_callback_.is_null())
+      return false;
+    constexpr int client_id = 1;
+    mojo::ScopedMessagePipeHandle handle;
+    base::ResetAndReturn(&establish_channel_callback_)
+        .Run(client_id, std::move(handle), gpu::GPUInfo());
+    return true;
+  }
+
+  // ui::mojom::Gpu overrides:
+  void EstablishGpuChannel(
+      const EstablishGpuChannelCallback& callback) override {
+    establish_channel_callback_ = callback;
+    if (!quit_closure_.is_null())
+      quit_closure_.Run();
+  }
+
+  void CreateGpuMemoryBuffer(
+      gfx::GpuMemoryBufferId id,
+      const gfx::Size& size,
+      gfx::BufferFormat format,
+      gfx::BufferUsage usage,
+      const ui::mojom::Gpu::CreateGpuMemoryBufferCallback& callback) override {}
+
+  void DestroyGpuMemoryBuffer(gfx::GpuMemoryBufferId id,
+                              const gpu::SyncToken& sync_token) override {}
+
+ private:
+  EstablishGpuChannelCallback establish_channel_callback_;
+
+  mojo::BindingSet<mojom::Gpu> bindings_;
+  base::Closure quit_closure_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestGpuImpl);
+};
+
+}  // namespace
+
+class GpuTest : public testing::Test {
+ public:
+  GpuTest() {}
+  ~GpuTest() override {}
+
+  Gpu* gpu() { return gpu_.get(); }
+
+  TestGpuImpl* gpu_impl() { return &gpu_impl_; }
+
+  // testing::Test:
+  void SetUp() override {
+    auto factory =
+        base::BindRepeating(&TestGpuImpl::GetPtr, base::Unretained(&gpu_impl_));
+    gpu_ = base::WrapUnique(new Gpu(std::move(factory), nullptr));
+  }
+
+ private:
+  base::test::ScopedTaskEnvironment env_;
+  TestGpuImpl gpu_impl_;
+  std::unique_ptr<Gpu> gpu_;
+
+  DISALLOW_COPY_AND_ASSIGN(GpuTest);
+};
+
+// Tests that multiple calls for establishing a gpu channel are all notified
+// correctly when the channel is established (or fails to establish).
+TEST_F(GpuTest, EstablishRequestsQueued) {
+  int counter = 2;
+  base::RunLoop run_loop;
+  // A callback that decrements the counter, and runs the callback when the
+  // counter reaches 0.
+  auto callback = base::Bind(
+      [](int* counter, const base::Closure& callback,
+         scoped_refptr<gpu::GpuChannelHost> channel) {
+        --(*counter);
+        if (*counter == 0)
+          callback.Run();
+      },
+      &counter, run_loop.QuitClosure());
+  gpu()->EstablishGpuChannel(callback);
+  gpu()->EstablishGpuChannel(callback);
+  EXPECT_EQ(2, counter);
+  gpu_impl()->WaitUntilChannelRequest();
+
+  EXPECT_TRUE(gpu_impl()->RespondToGpuChannelRequests());
+  run_loop.Run();
+  EXPECT_EQ(0, counter);
+}
+
+}  // namespace ui