viz: Replace a DCHECK with proper error handling.

components/viz/common/server_gpu_memory_buffer_manager_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 "components/viz/common/server_gpu_memory_buffer_manager.h"
 
 #include "base/test/scoped_task_environment.h"
 #include "gpu/ipc/host/gpu_memory_buffer_support.h"
 #include "services/ui/gpu/interfaces/gpu_service.mojom.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 190 matching lines @@
   EXPECT_TRUE(gpu_service.HasAllocationRequest(buffer_id, client_id));
   EXPECT_FALSE(gpu_service.HasDestructionRequest(buffer_id, client_id));
 
   // When the host receives the allocated memory for the destroyed client, it
   // should request the allocated memory to be freed.
   gpu_service.SatisfyAllocationRequest(buffer_id, client_id);
   EXPECT_TRUE(gpu_service.HasDestructionRequest(buffer_id, client_id));
 #endif
 }
 
+TEST_F(ServerGpuMemoryBufferManagerTest,
+       RequestsFromUntrustedClientsValidated) {
+  gfx::ClientNativePixmapFactory::ResetInstance();
+  TestGpuService gpu_service;
+  ServerGpuMemoryBufferManager manager(&gpu_service, 1);
+  const auto buffer_id = static_cast<gfx::GpuMemoryBufferId>(1);
+  const int client_id = 2;
+  const gfx::Size size(10, 20);
+  // SCANOUT cannot be used if native gpu memory buffer is not supported.
+  struct {
+    gfx::BufferUsage usage;
+    gfx::BufferFormat format;
+    bool expect_null_handle;
+  } configs[] = {
+      {gfx::BufferUsage::SCANOUT, gfx::BufferFormat::YVU_420, true},
+      {gfx::BufferUsage::GPU_READ, gfx::BufferFormat::YVU_420, false},
+  };
+  for (const auto& config : configs) {
+    gfx::GpuMemoryBufferHandle allocated_handle;
+    base::RunLoop runloop;
+    manager.AllocateGpuMemoryBuffer(
+        buffer_id, client_id, size, config.format, config.usage,
+        gpu::kNullSurfaceHandle,
+        base::BindOnce(
+            [](gfx::GpuMemoryBufferHandle* allocated_handle,
+               const base::Closure& callback,
+               const gfx::GpuMemoryBufferHandle& handle) {
+              *allocated_handle = handle;
+              callback.Run();
+            },
+            &allocated_handle, runloop.QuitClosure()));
+    // Since native gpu memory buffers are not supported, the mojom.GpuService
+    // should not receive any allocation requests.
+    EXPECT_FALSE(gpu_service.HasAllocationRequest(buffer_id, client_id));
+    runloop.Run();
+    if (config.expect_null_handle) {
+      EXPECT_TRUE(allocated_handle.is_null());
+    } else {
+      EXPECT_FALSE(allocated_handle.is_null());
+      EXPECT_EQ(gfx::GpuMemoryBufferType::SHARED_MEMORY_BUFFER,
+                allocated_handle.type);
+    }
+  }

[danakj, 2017/06/26 15:43:42]

Can you add something that shows we actually hit both branches? Else this test
could in the future break in some way and only hit one branch and we'd never
know.

[sadrul, 2017/06/26 21:48:58]

Good point. Done.

+}
+
 }  // namespace viz