Resource leak when rotating the screen on Android with Impeller/Vulkan #190114

On some platforms Impeller/Vulkan is leaking resources each time the screen is rotated.

Reproduced this on a Pixel 6a.

• Run the default template app
• In adb shell, run this to get a count of file descriptors opened by the app process:

APP=[app package name]
run-as $APP ls /proc/`pidof $APP`/fd | wc

• Rotate the screen repeatedly. The count of file descriptors will increase each time the app window is resized.

On the Pixel 6a, each rotation adds a pair of dmabuf file descriptors:

160 -> /dmabuf:system
161 -> /dmabuf:f2bb30a SurfaceView[com.example

Debugged this and found that the leak is coming from KHRSwapchainVK.

When the window changes its size, KHRSwapchainVK::AcquireNextDrawable was calling vkAcquireNextImageKHR but never presenting the acquired image.

KHRSwapchainVK::AcquireNextDrawable would then call vkDestroySwapchainKHR on the swapchain associated with the old size. But vkDestroySwapchainKHR requires completion of all operations on images acquired from the swapchain before destroying the swapchain. The extra image that was acquired but not presented apparently resulted in leaks.