Add WSI functions to GrVkInterface

src/gpu/vk/GrVkBackendContext.cpp

Index: src/gpu/vk/GrVkBackendContext.cpp
diff --git a/src/gpu/vk/GrVkBackendContext.cpp b/src/gpu/vk/GrVkBackendContext.cpp
index ccc834788f603aade7a3a3f0ca87ad87a154de35..b6cc3dd3ed9ed8b88f04e1967e54740df380d885 100644
--- a/src/gpu/vk/GrVkBackendContext.cpp
+++ b/src/gpu/vk/GrVkBackendContext.cpp
@@ -68,6 +68,30 @@ const GrVkBackendContext* GrVkBackendContext::Create() {
         instanceExtensionNames.push_back(VK_EXT_DEBUG_REPORT_EXTENSION_NAME);
         extensionFlags |= kEXT_debug_report_GrVkExtensionFlag;
     }
+    if (extensions.hasInstanceExtension(VK_KHR_SURFACE_EXTENSION_NAME)) {
+        instanceExtensionNames.push_back(VK_KHR_SURFACE_EXTENSION_NAME);
+        extensionFlags |= kKHR_surface_GrVkExtensionFlag;
+    }
+    if (extensions.hasInstanceExtension(VK_KHR_SWAPCHAIN_EXTENSION_NAME)) {
+        instanceExtensionNames.push_back(VK_KHR_SWAPCHAIN_EXTENSION_NAME);
+        extensionFlags |= kKHR_swapchain_GrVkExtensionFlag;
+    }
+#ifdef SK_BUILD_FOR_WIN
+    if (extensions.hasInstanceExtension(VK_KHR_WIN32_SURFACE_EXTENSION_NAME)) {
+        instanceExtensionNames.push_back(VK_KHR_WIN32_SURFACE_EXTENSION_NAME);
+        extensionFlags |= kKHR_win32_surface_GrVkExtensionFlag;
+    }
+#elif SK_BUILD_FOR_ANDROID
+    if (extensions.hasInstanceExtension(VK_KHR_ANDROID_SURFACE_EXTENSION_NAME)) {
+        instanceExtensionNames.push_back(VK_KHR_ANDROID_SURFACE_EXTENSION_NAME);
+        extensionFlags |= kKHR_android_surface_GrVkExtensionFlag;
+}
+#elif SK_BUILD_FOR_UNIX
+    if (extensions.hasInstanceExtension(VK_KHR_XLIB_SURFACE_EXTENSION_NAME)) {
+        instanceExtensionNames.push_back(VK_KHR_XLIB_SURFACE_EXTENSION_NAME);
+        extensionFlags |= kKHR_xlib_surface_GrVkExtensionFlag;
+    }
+#endif
 #endif
 
     const VkInstanceCreateInfo instance_create = {