Make Vulkan's surface config available before the swap chain is actually created/

Change-Id: I9da1c9f513d26aa95b40f97908bfc3a54c843053
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/15541
Commit-Queue: Mark Henderson <mehe@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>

src/dawn_native/vulkan/NativeSwapChainImplVk.cpp

@@ -66,6 +66,9 @@ namespace dawn_native { namespace vulkan {
 
     NativeSwapChainImpl::NativeSwapChainImpl(Device* device, VkSurfaceKHR surface)
         : mSurface(surface), mDevice(device) {
+        // Call this immediately, so that BackendBinding::GetPreferredSwapChainTextureFormat
+        // will return a correct result before a SwapChain is created.
+        UpdateSurfaceConfig();
     }
 
     NativeSwapChainImpl::~NativeSwapChainImpl() {