[Impeller] Fix swapchain recreation for non-polling cases.

impeller/renderer/backend/vulkan/surface_context_vk.cc

@@ -69,13 +69,14 @@ bool SurfaceContextVK::SetWindowSurface(vk::UniqueSurfaceKHR surface) {
 std::unique_ptr<Surface> SurfaceContextVK::AcquireNextSurface() {
   TRACE_EVENT0("impeller", __FUNCTION__);
   auto surface = swapchain_ ? swapchain_->AcquireNextDrawable() : nullptr;
-  auto pipeline_library = parent_->GetPipelineLibrary();
-  if (surface && pipeline_library) {
+  if (!surface) {
+    return nullptr;
+  }
+  if (auto pipeline_library = parent_->GetPipelineLibrary()) {
     impeller::PipelineLibraryVK::Cast(*pipeline_library)
         .DidAcquireSurfaceFrame();
   }
-  auto allocator = parent_->GetResourceAllocator();
-  if (allocator) {
+  if (auto allocator = parent_->GetResourceAllocator()) {
     allocator->DidAcquireSurfaceFrame();
   }
   return surface;

impeller/renderer/backend/vulkan/swapchain_impl_vk.cc

@@ -375,15 +375,20 @@ SwapchainImplVK::AcquireResult SwapchainImplVK::AcquireNextDrawable() {
       nullptr               // fence
   );
 
-  if (acq_result == vk::Result::eErrorOutOfDateKHR) {
-    return AcquireResult{true /* out of date */};
-  }
-
-  if (acq_result != vk::Result::eSuccess &&
-      acq_result != vk::Result::eSuboptimalKHR) {
-    VALIDATION_LOG << "Could not acquire next swapchain image: "
-                   << vk::to_string(acq_result);
-    return {};
+  switch (acq_result) {
+    case vk::Result::eSuccess:
+      // Keep going.
+      break;
+    case vk::Result::eSuboptimalKHR:
+    case vk::Result::eErrorOutOfDateKHR:
+      // A recoverable error. Just say we are out of date.
+      return AcquireResult{true /* out of date */};
+      break;
+    default:
+      // An unrecoverable error.
+      VALIDATION_LOG << "Could not acquire next swapchain image: "
+                     << vk::to_string(acq_result);
+      return AcquireResult{false /* out of date */};
   }
 
   if (index >= images_.size()) {