[Impeller] VkImageView leak in WrappedTextureSourceVK (embedder delegate path) #181967

Description

WrappedTextureSourceVK in shell/gpu/gpu_surface_vulkan_impeller.cc leaks a VkImageView every frame when using the embedder delegate code path.

Steps to reproduce

1. Create a custom embedder using FlutterVulkanRendererConfig (the Vulkan delegate path)
2. Run any Flutter app
3. Each frame, AcquireFrame calls createImageView() and stores the result as a raw vk::ImageView
4. The destructor ~WrappedTextureSourceVK() {} is empty — the VkImageView is never destroyed

This leaks ~60 VkImageView handles per second. On a long-running app this will eventually exhaust driver resources.

Analysis

The fix is straightforward: use vk::UniqueImageView instead of raw vk::ImageView for RAII ownership. The resource lifetime is safe because Impeller's TrackedObjectsVK holds a shared_ptr<TextureSourceVK> until the GPU fence signals completion, preventing premature destruction.

This only affects the embedder delegate path (delegate_ != nullptr). Android passes nullptr as the delegate and uses AcquireNextSurface() instead, so Android is not affected.

Environment

• Found on Linux/Wayland with a custom Vulkan embedder
• NVIDIA GeForce RTX 5070 Ti, driver 570.x
• Flutter engine at commit f916dd6

Labels

• e: impeller
• platform-linux
• P2