Updates DawnInstanceDescriptor to pass in the Platform.

Notes:
- Separates ChainedStruct to be reusable without cpp header. (Also
  updates native structs to directly use it.)
- Manually implements the descriptor in DawnNative.
- Reworks ChainUtils with mapping from struct to STypes.
- Updates the tests to use either SetPlatformForTesting which is still
  required because DawnTest uses a "global" instance for all tests and
  some tests require setting (and cleaning up) a test specific platform.

Bug: dawn:1374
Change-Id: I078c78f22c5137030cf3cf0e8358fe4373ee9c6c
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/132268
Reviewed-by: Austin Eng <enga@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Loko Kung <lokokung@google.com>

src/dawn/native/DawnNative.cpp

@@ -135,6 +135,19 @@ void Adapter::ResetInternalDeviceForTesting() {
 AdapterDiscoveryOptionsBase::AdapterDiscoveryOptionsBase(WGPUBackendType type)
     : backendType(type) {}
 
+// DawnInstanceDescriptor
+
+DawnInstanceDescriptor::DawnInstanceDescriptor() {
+    sType = wgpu::SType::DawnInstanceDescriptor;
+}
+
+bool DawnInstanceDescriptor::operator==(const DawnInstanceDescriptor& rhs) const {
+    return (nextInChain == rhs.nextInChain) &&
+           std::tie(additionalRuntimeSearchPathsCount, additionalRuntimeSearchPaths, platform) ==
+               std::tie(rhs.additionalRuntimeSearchPathsCount, rhs.additionalRuntimeSearchPaths,
+                        rhs.platform);
+}
+
 // Instance
 
 Instance::Instance(const WGPUInstanceDescriptor* desc)

src/dawn/native/Instance.cpp

@@ -186,7 +186,7 @@ MaybeError InstanceBase::Initialize(const InstanceDescriptor* descriptor) {
 
     // Initialize the platform to the default for now.
     mDefaultPlatform = std::make_unique<dawn::platform::Platform>();
-    SetPlatform(mDefaultPlatform.get());
+    SetPlatform(dawnDesc != nullptr ? dawnDesc->platform : mDefaultPlatform.get());
 
     return {};
 }

src/dawn/tests/DawnNativeTest.cpp

@@ -49,19 +49,21 @@ void DawnNativeTest::SetUp() {
     // adapter and device toggles and allow us to test unsafe apis (including experimental
     // features).
     const char* allowUnsafeApisToggle = "allow_unsafe_apis";
-    WGPUDawnTogglesDescriptor instanceToggles = {};
-    instanceToggles.chain.sType = WGPUSType::WGPUSType_DawnTogglesDescriptor;
+    wgpu::DawnTogglesDescriptor instanceToggles;
     instanceToggles.enabledTogglesCount = 1;
     instanceToggles.enabledToggles = &allowUnsafeApisToggle;
 
-    WGPUInstanceDescriptor instanceDesc = {};
-    instanceDesc.nextInChain = &instanceToggles.chain;
-
-    instance = std::make_unique<dawn::native::Instance>(&instanceDesc);
-    instance->EnableAdapterBlocklist(false);
     platform = CreateTestPlatform();
-    dawn::native::FromAPI(instance->Get())->SetPlatformForTesting(platform.get());
+    wgpu::DawnInstanceDescriptor dawnInstanceDesc;
+    dawnInstanceDesc.platform = platform.get();
+    dawnInstanceDesc.nextInChain = &instanceToggles;
 
+    wgpu::InstanceDescriptor instanceDesc;
+    instanceDesc.nextInChain = &dawnInstanceDesc;
+
+    instance = std::make_unique<dawn::native::Instance>(
+        reinterpret_cast<const WGPUInstanceDescriptor*>(&instanceDesc));
+    instance->EnableAdapterBlocklist(false);
     instance->DiscoverDefaultAdapters();
 
     std::vector<dawn::native::Adapter> adapters = instance->GetAdapters();

src/dawn/tests/DawnTest.cpp

@@ -373,20 +373,25 @@ void DawnTestEnvironment::ParseArgs(int argc, char** argv) {
     }
 }
 
-std::unique_ptr<dawn::native::Instance> DawnTestEnvironment::CreateInstanceAndDiscoverAdapters() {
+std::unique_ptr<dawn::native::Instance> DawnTestEnvironment::CreateInstanceAndDiscoverAdapters(
+    dawn::platform::Platform* platform) {
     // Create an instance with toggle AllowUnsafeAPIs enabled, which would be inherited to
     // adapter and device toggles and allow us to test unsafe apis (including experimental
     // features).
     const char* allowUnsafeApisToggle = "allow_unsafe_apis";
-    WGPUDawnTogglesDescriptor instanceToggles = {};
-    instanceToggles.chain.sType = WGPUSType::WGPUSType_DawnTogglesDescriptor;
+    wgpu::DawnTogglesDescriptor instanceToggles;
     instanceToggles.enabledTogglesCount = 1;
     instanceToggles.enabledToggles = &allowUnsafeApisToggle;
 
-    WGPUInstanceDescriptor instanceDesc = {};
-    instanceDesc.nextInChain = &instanceToggles.chain;
+    wgpu::DawnInstanceDescriptor dawnInstanceDesc;
+    dawnInstanceDesc.platform = platform;
+    dawnInstanceDesc.nextInChain = &instanceToggles;
 
-    auto instance = std::make_unique<dawn::native::Instance>(&instanceDesc);
+    wgpu::InstanceDescriptor instanceDesc;
+    instanceDesc.nextInChain = &dawnInstanceDesc;
+
+    auto instance = std::make_unique<dawn::native::Instance>(
+        reinterpret_cast<const WGPUInstanceDescriptor*>(&instanceDesc));
     instance->EnableBeginCaptureOnStartup(mBeginCaptureOnStartup);
     instance->SetBackendValidationLevel(mBackendValidationLevel);
     instance->EnableAdapterBlocklist(false);
@@ -1096,6 +1101,9 @@ void DawnTestBase::TearDown() {
         EXPECT_EQ(mLastWarningCount,
                   dawn::native::GetDeprecationWarningCountForTesting(device.Get()));
     }
+
+    // Unsets the platform since we are cleaning the per-test platform up with the test case.
+    dawn::native::FromAPI(gTestEnv->GetInstance()->Get())->SetPlatformForTesting(nullptr);
 }
 
 void DawnTestBase::DestroyDevice(wgpu::Device device) {

src/dawn/tests/DawnTest.h

@@ -183,11 +183,12 @@ class DawnTestEnvironment : public testing::Environment {
     bool RunSuppressedTests() const;
 
   protected:
+    std::unique_ptr<dawn::native::Instance> CreateInstanceAndDiscoverAdapters(
+        dawn::platform::Platform* platform = nullptr);
     std::unique_ptr<dawn::native::Instance> mInstance;
 
   private:
     void ParseArgs(int argc, char** argv);
-    std::unique_ptr<dawn::native::Instance> CreateInstanceAndDiscoverAdapters();
     void SelectPreferredAdapterProperties(const dawn::native::Instance* instance);
     void PrintTestConfigurationAndAdapterInfo(dawn::native::Instance* instance) const;
 

src/dawn/tests/perf_tests/DawnPerfTest.cpp

@@ -122,10 +122,9 @@ DawnPerfTestEnvironment::DawnPerfTestEnvironment(int argc, char** argv)
 DawnPerfTestEnvironment::~DawnPerfTestEnvironment() = default;
 
 void DawnPerfTestEnvironment::SetUp() {
-    DawnTestEnvironment::SetUp();
-
     mPlatform = std::make_unique<DawnPerfTestPlatform>();
-    mInstance->SetPlatform(mPlatform.get());
+    mInstance = CreateInstanceAndDiscoverAdapters(mPlatform.get());
+    ASSERT(mInstance);
 
     // Begin writing the trace event array.
     if (mTraceFile != nullptr) {