Use Windowing system-specific WindowContext factories.

tools/viewer/sk_app/win/VulkanWindowContext_win.cpp

Index: tools/viewer/sk_app/win/VulkanWindowContext_win.cpp
diff --git a/tools/viewer/sk_app/win/VulkanWindowContext_win.cpp b/tools/viewer/sk_app/win/VulkanWindowContext_win.cpp
index e4251b88cfca6063de433752a7487c2d49b47cb3..521a1ee3cd8f1d5d2963d56ce46c181c01d3b239 100644
--- a/tools/viewer/sk_app/win/VulkanWindowContext_win.cpp
+++ b/tools/viewer/sk_app/win/VulkanWindowContext_win.cpp
@@ -6,6 +6,9 @@
  * found in the LICENSE file.
  */
 
+#include <Windows.h>
+#include "WindowContextFactory_win.h"
+
 #include "../VulkanWindowContext.h"
 #include "Window_win.h"
 
@@ -13,51 +16,56 @@
 #include "vk/GrVkUtil.h"
 
 namespace sk_app {
+namespace window_context_factory {
 
-// Platform dependant call
-VkSurfaceKHR VulkanWindowContext::createVkSurface(VkInstance instance, void* platformData) {
-    static PFN_vkCreateWin32SurfaceKHR createWin32SurfaceKHR = nullptr;
-    if (!createWin32SurfaceKHR) {
-        createWin32SurfaceKHR = (PFN_vkCreateWin32SurfaceKHR) vkGetInstanceProcAddr(instance,
-                                                                        "vkCreateWin32SurfaceKHR");
-    }
+WindowContext* NewVulkanForWin(HWND hwnd, const DisplayParams& params) {
+    auto createVkSurface = [hwnd] (VkInstance instance) -> VkSurfaceKHR {
+        static PFN_vkCreateWin32SurfaceKHR createWin32SurfaceKHR = nullptr;
+        if (!createWin32SurfaceKHR) {
+            createWin32SurfaceKHR = (PFN_vkCreateWin32SurfaceKHR)
+                vkGetInstanceProcAddr(instance, "vkCreateWin32SurfaceKHR");
+        }
+        HINSTANCE hinstance = GetModuleHandle(0);
+        VkSurfaceKHR surface;
 
-    if (!platformData) {
-        return VK_NULL_HANDLE;
-    }
-    ContextPlatformData_win* winPlatformData =
-                                          reinterpret_cast<ContextPlatformData_win*>(platformData);
-    VkSurfaceKHR surface;
-
-    VkWin32SurfaceCreateInfoKHR surfaceCreateInfo;
-    memset(&surfaceCreateInfo, 0, sizeof(VkWin32SurfaceCreateInfoKHR));
-    surfaceCreateInfo.sType = VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR;
-    surfaceCreateInfo.pNext = nullptr;
-    surfaceCreateInfo.flags = 0;
-    surfaceCreateInfo.hinstance = winPlatformData->fHInstance;
-    surfaceCreateInfo.hwnd = winPlatformData->fHWnd;
-
-    VkResult res = createWin32SurfaceKHR(instance, &surfaceCreateInfo, nullptr, &surface);
-    if (VK_SUCCESS != res) {
-        return VK_NULL_HANDLE;
-    }
+        VkWin32SurfaceCreateInfoKHR surfaceCreateInfo;
+        memset(&surfaceCreateInfo, 0, sizeof(VkWin32SurfaceCreateInfoKHR));
+        surfaceCreateInfo.sType = VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR;
+        surfaceCreateInfo.pNext = nullptr;
+        surfaceCreateInfo.flags = 0;
+        surfaceCreateInfo.hinstance = hinstance;
+        surfaceCreateInfo.hwnd = hwnd;
 
-    return surface;
-}
+        VkResult res = createWin32SurfaceKHR(instance, &surfaceCreateInfo, nullptr, &surface);
+        if (VK_SUCCESS != res) {
+            return VK_NULL_HANDLE;
+        }
 
-// Platform dependant call
-bool VulkanWindowContext::canPresent(VkInstance instance, VkPhysicalDevice physDev,
-                                     uint32_t queueFamilyIndex, void*) {
-    static PFN_vkGetPhysicalDeviceWin32PresentationSupportKHR
+        return surface;
+    };
+
+    auto canPresent = [hwnd] (VkInstance instance, VkPhysicalDevice physDev,
+                             uint32_t queueFamilyIndex) {
+        static PFN_vkGetPhysicalDeviceWin32PresentationSupportKHR
                                             getPhysicalDeviceWin32PresentationSupportKHR = nullptr;
-    if (!getPhysicalDeviceWin32PresentationSupportKHR) {
-        getPhysicalDeviceWin32PresentationSupportKHR =
-            (PFN_vkGetPhysicalDeviceWin32PresentationSupportKHR) vkGetInstanceProcAddr(instance,
-                                                 "vkGetPhysicalDeviceWin32PresentationSupportKHR");
-    }
+        if (!getPhysicalDeviceWin32PresentationSupportKHR) {
+            getPhysicalDeviceWin32PresentationSupportKHR =
+                (PFN_vkGetPhysicalDeviceWin32PresentationSupportKHR)
+                    vkGetInstanceProcAddr(instance,
+                                          "vkGetPhysicalDeviceWin32PresentationSupportKHR");
+        }
 
-    VkBool32 check = getPhysicalDeviceWin32PresentationSupportKHR(physDev, queueFamilyIndex);
-    return (VK_FALSE != check);
+        VkBool32 check = getPhysicalDeviceWin32PresentationSupportKHR(physDev, queueFamilyIndex);
+        return (VK_FALSE != check);
+    };
+
+    WindowContext* ctx = new VulkanWindowContext(params, createVkSurface, canPresent);
+    if (!ctx->isValid()) {
+        delete ctx;
+        return nullptr;
+    }
+    return ctx;
 }
 
-}   // namespace sk_app
+}  // namespace window_context_factory
+}  // namespace sk_app