Initial new swapchains on Vulkan.

Bug: dawn:269

Change-Id: I5b7a4edfa876d5a64f8f135adb619be021e4f534
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/17966
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
diff --git a/examples/SampleUtils.cpp b/examples/SampleUtils.cpp
index 174b539..f1fbb6c 100644
--- a/examples/SampleUtils.cpp
+++ b/examples/SampleUtils.cpp
@@ -96,6 +96,7 @@
 
     // Create the test window and discover adapters using it (esp. for OpenGL)
     utils::SetupGLFWWindowHintsForBackend(backendType);
+    glfwWindowHint(GLFW_COCOA_RETINA_FRAMEBUFFER, GLFW_FALSE);
     window = glfwCreateWindow(640, 480, "Dawn window", nullptr, nullptr);
     if (!window) {
         return wgpu::Device();