viz: Replace a DCHECK with proper error handling.

components/viz/common/server_gpu_memory_buffer_manager_unittest.cc

Index: components/viz/common/server_gpu_memory_buffer_manager_unittest.cc
diff --git a/components/viz/common/server_gpu_memory_buffer_manager_unittest.cc b/components/viz/common/server_gpu_memory_buffer_manager_unittest.cc
index 766852975f9059487ab968c0a6d023ed16969dc5..5d7feafeffb92a4a75c9cbb5d2c114d7aff0464c 100644
--- a/components/viz/common/server_gpu_memory_buffer_manager_unittest.cc
+++ b/components/viz/common/server_gpu_memory_buffer_manager_unittest.cc
@@ -208,4 +208,49 @@ TEST_F(ServerGpuMemoryBufferManagerTest, AllocationRequestsForDestroyedClient) {
 #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