iOS,macOS: Refactor TestMetalContext for ARC

testing/test_metal_context.h

@@ -6,13 +6,16 @@
 #define FLUTTER_TESTING_TEST_METAL_CONTEXT_H_
 
 #include <map>
+#include <memory>
 #include <mutex>
 
 #include "third_party/skia/include/gpu/ganesh/GrDirectContext.h"
 #include "third_party/skia/include/ports/SkCFObject.h"
 
 namespace flutter {
 
+struct MetalObjCFields;
+
 class TestMetalContext {
  public:
   struct TextureInfo {
@@ -38,9 +41,7 @@ class TestMetalContext {
   TextureInfo GetTextureInfo(int64_t texture_id);
 
  private:
-  // TODO(cbracken): https://github.com/flutter/flutter/issues/157942
-  void* device_;         // id<MTLDevice>
-  void* command_queue_;  // id<MTLCommandQueue>
+  std::unique_ptr<MetalObjCFields> metal_;
   sk_sp<GrDirectContext> skia_context_;
   std::mutex textures_mutex_;
   int64_t texture_id_ctr_ = 1;                 // guarded by textures_mutex

testing/test_metal_context.mm

@@ -17,6 +17,12 @@
 
 namespace flutter {
 
+// TOOD(cbracken): https://github.com/flutter/flutter/issues/157942
+struct MetalObjCFields {
+  id<MTLDevice> device;
+  id<MTLCommandQueue> command_queue;
+};
+
 TestMetalContext::TestMetalContext() {
   id<MTLDevice> device = MTLCreateSystemDefaultDevice();
   if (!device) {
@@ -43,37 +49,21 @@
                       "and command queue.";
   }
 
-  // Retain and transfer to non-ARC-managed pointers.
-  // TODO(cbracken): https://github.com/flutter/flutter/issues/157942
-  device_ = (__bridge_retained void*)device;
-  command_queue_ = (__bridge_retained void*)command_queue;
+  metal_ = std::make_unique<MetalObjCFields>(MetalObjCFields{device, command_queue});
 }
 
 TestMetalContext::~TestMetalContext() {
   std::scoped_lock lock(textures_mutex_);
   textures_.clear();
-  if (device_) {
-    // Release and transfer to ARC-managed pointer.
-    // TODO(cbracken): https://github.com/flutter/flutter/issues/157942
-    id<MTLDevice> device =  // NOLINT(clang-analyzer-deadcode.DeadStores)
-        (__bridge_transfer id<MTLDevice>)device_;
-    device = nil;
-  }
-  if (command_queue_) {
-    // Release and transfer to ARC-managed pointer.
-    // TODO(cbracken): https://github.com/flutter/flutter/issues/157942
-    id<MTLCommandQueue> command_queue =  // NOLINT(clang-analyzer-deadcode.DeadStores)
-        (__bridge_transfer id<MTLCommandQueue>)command_queue_;
-    command_queue = nil;
-  }
+  metal_.reset();
 }
 
 void* TestMetalContext::GetMetalDevice() const {
-  return device_;
+  return metal_ ? (__bridge void*)metal_->device : nil;
 }
 
 void* TestMetalContext::GetMetalCommandQueue() const {
-  return command_queue_;
+  return metal_ ? (__bridge void*)metal_->command_queue : nil;
 }
 
 sk_sp<GrDirectContext> TestMetalContext::GetSkiaContext() const {
@@ -98,8 +88,12 @@
     return {.texture_id = -1, .texture = nullptr};
   }
 
-  id<MTLDevice> device = (__bridge id<MTLDevice>)GetMetalDevice();
-  id<MTLTexture> texture = [device newTextureWithDescriptor:texture_descriptor];
+  if (!metal_) {
+    FML_CHECK(false) << "Invalid Metal device.";
+    return {.texture_id = -1, .texture = nullptr};
+  }
+
+  id<MTLTexture> texture = [metal_->device newTextureWithDescriptor:texture_descriptor];
   if (!texture) {
     FML_CHECK(false) << "Could not create texture from texture descriptor.";
     return {.texture_id = -1, .texture = nullptr};