vk: fix leaking swapchains again (#9410)

- Adjust order of destroy call in both headless and platform
   swapchains.  We need to be careful of the order due to
   assumptions made by the base class's destroy().
 - remove `=0` since VulkanPlatformSwapChainBase::destroy() has
   an implementation.

Fixes #9403

filament/backend/src/vulkan/platform/VulkanPlatformSwapChainImpl.cpp

@@ -408,7 +408,6 @@ VkResult VulkanPlatformSurfaceSwapChain::recreate() {
 }
 
 void VulkanPlatformSurfaceSwapChain::destroy() {
-    VulkanPlatformSwapChainBase::destroy();
     // The next part is not ideal. We don't have a good signal on when it's ok to destroy
     // a swapchain. This is a spec oversight and mentioned as much:
     // https://github.com/KhronosGroup/Vulkan-Docs/issues/1678
@@ -425,6 +424,8 @@ void VulkanPlatformSurfaceSwapChain::destroy() {
     // phone). If necessary, we can revisit and implement the workaround [1].
     vkQueueWaitIdle(mQueue);
 
+    VulkanPlatformSwapChainBase::destroy();
+
     for (uint32_t i = 0; i < IMAGE_READY_SEMAPHORE_COUNT; ++i) {
         if (mImageReady[i] != VK_NULL_HANDLE) {
             vkDestroySemaphore(mDevice, mImageReady[i], VKALLOC);
@@ -475,7 +476,6 @@ VkResult VulkanPlatformHeadlessSwapChain::acquire(VulkanPlatform::ImageSyncData*
 }
 
 void VulkanPlatformHeadlessSwapChain::destroy() {
-    VulkanPlatformSwapChainBase::destroy();
     // This is only ever called from the destructor since headless does not recreate.
     for (auto image: mSwapChainBundle.colors) {
         vkDestroyImage(mDevice, image, VKALLOC);
@@ -485,7 +485,10 @@ void VulkanPlatformHeadlessSwapChain::destroy() {
         }
     }
     mSwapChainBundle.colors.clear();
-    // No need to manually call through to the super because the super's destructor will be called
+
+    // Still need to call through to free the depth image.  But must do it after releasing the color
+    // images.
+    VulkanPlatformSwapChainBase::destroy();
 }
 
 }// namespace filament::backend

filament/backend/src/vulkan/platform/VulkanPlatformSwapChainImpl.h

@@ -62,7 +62,7 @@ struct VulkanPlatformSwapChainBase : public Platform::SwapChain {
     virtual bool queryFrameTimestamps(uint64_t frameId, FrameTimestamps* outFrameTimestamps) const;
 
 protected:
-    virtual void destroy() = 0;
+    virtual void destroy();
 
     VkImage createImage(VkExtent2D extent, VkFormat format, bool isProtected);