Remove unused SwapChainImplVulkan

BUG=dawn:29

Change-Id: Ic36bdd83b2351e3ef9d6825dee64469405e840a3
Reviewed-on: https://dawn-review.googlesource.com/c/3660
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

src/utils/VulkanBinding.cpp

@@ -22,32 +22,6 @@
 
 namespace utils {
 
-    class SwapChainImplVulkan {
-      public:
-        using WSIContext = dawnWSIContextVulkan;
-
-        SwapChainImplVulkan(GLFWwindow* /*window*/) {
-        }
-
-        ~SwapChainImplVulkan() {
-        }
-
-        void Init(dawnWSIContextVulkan*) {
-        }
-
-        dawnSwapChainError Configure(dawnTextureFormat, dawnTextureUsageBit, uint32_t, uint32_t) {
-            return DAWN_SWAP_CHAIN_NO_ERROR;
-        }
-
-        dawnSwapChainError GetNextTexture(dawnSwapChainNextTexture*) {
-            return DAWN_SWAP_CHAIN_NO_ERROR;
-        }
-
-        dawnSwapChainError Present() {
-            return DAWN_SWAP_CHAIN_NO_ERROR;
-        }
-    };
-
     class VulkanBinding : public BackendBinding {
       public:
         void SetupGLFWWindowHints() override {