Merge changes I6ea2e33e,Iccfce003

* changes:
  vulkan: Add function stub & plumbing for KHR_swapchain_front_buffered
  vulkan: Add KHR_swapchain_front_buffered to header and api
diff --git a/vulkan/api/vulkan.api b/vulkan/api/vulkan.api
index df45c20..1023182 100644
--- a/vulkan/api/vulkan.api
+++ b/vulkan/api/vulkan.api
@@ -150,6 +150,9 @@
 @extension("VK_NVX_device_generated_commands") define VK_NVX_DEVICE_GENERATED_COMMANDS_SPEC_VERSION 1
 @extension("VK_NVX_device_generated_commands") define VK_NVX_DEVICE_GENERATED_COMMANDS_EXTENSION_NAME "VK_NVX_device_generated_commands"
 
+@extension("VK_KHR_swapchain_front_buffered") define VK_KHR_SWAPCHAIN_FRONT_BUFFERED_SPEC_VERSION 2
+@extension("VK_KHR_swapchain_front_buffered") define VK_KHR_SWAPCHAIN_FRONT_BUFFERED_EXTENSION_NAME "VK_KHR_swapchain_front_buffered"
+
 
 
 /////////////
@@ -924,6 +927,10 @@
     VK_PRESENT_MODE_MAILBOX_KHR                             = 0x00000001,
     VK_PRESENT_MODE_FIFO_KHR                                = 0x00000002,
     VK_PRESENT_MODE_FIFO_RELAXED_KHR                        = 0x00000003,
+    //@extension("VK_KHR_swapchain_front_buffered")
+    VK_PRESENT_MODE_FRONT_BUFFERED_DEMAND_REFRESH_KHR       = 1000111000,
+    //@extension("VK_KHR_swapchain_front_buffered")
+    VK_PRESENT_MODE_FRONT_BUFFERED_CONTINUOUS_REFRESH_KHR   = 1000111001,
 }
 
 @extension("VK_KHR_surface")
@@ -6109,6 +6116,13 @@
         VkDeviceGeneratedCommandsLimitsNVX*         pLimits) {
 }
 
+@extension("VK_KHR_swapchain_front_buffered")
+cmd VkResult vkGetSwapchainStatusKHR(
+        VkDevice                                    device,
+        VkSwapchainKHR                              swapchain) {
+    return ?
+}
+
 
 ////////////////
 // Validation //
diff --git a/vulkan/include/vulkan/vulkan.h b/vulkan/include/vulkan/vulkan.h
index 6ddce8f..28c2440 100644
--- a/vulkan/include/vulkan/vulkan.h
+++ b/vulkan/include/vulkan/vulkan.h
@@ -3228,6 +3228,8 @@
     VK_PRESENT_MODE_MAILBOX_KHR = 1,
     VK_PRESENT_MODE_FIFO_KHR = 2,
     VK_PRESENT_MODE_FIFO_RELAXED_KHR = 3,
+    VK_PRESENT_MODE_FRONT_BUFFERED_DEMAND_REFRESH_KHR = 1000111000,
+    VK_PRESENT_MODE_FRONT_BUFFERED_CONTINUOUS_REFRESH_KHR = 1000111001,
     VK_PRESENT_MODE_BEGIN_RANGE_KHR = VK_PRESENT_MODE_IMMEDIATE_KHR,
     VK_PRESENT_MODE_END_RANGE_KHR = VK_PRESENT_MODE_FIFO_RELAXED_KHR,
     VK_PRESENT_MODE_RANGE_SIZE_KHR = (VK_PRESENT_MODE_FIFO_RELAXED_KHR - VK_PRESENT_MODE_IMMEDIATE_KHR + 1),
@@ -3884,6 +3886,18 @@
     const VkPresentRegionKHR* pRegions;
 } VkPresentRegionsKHR;
 
+#define VK_KHR_swapchain_front_buffered 1
+#define VK_KHR_SWAPCHAIN_FRONT_BUFFERED_SPEC_VERSION 2
+#define VK_KHR_SWAPCHAIN_FRONT_BUFFERED_EXTENSION_NAME "VK_KHR_swapchain_front_buffered"
+
+typedef VkResult (VKAPI_PTR *PFN_vkGetSwapchainStatusKHR)(VkDevice device, VkSwapchainKHR swapchain);
+
+#ifndef VK_NO_PROTOTYPES
+VKAPI_ATTR VkResult VKAPI_CALL vkGetSwapchainStatusKHR(
+    VkDevice                                    device,
+    VkSwapchainKHR                              swapchain);
+#endif
+
 #define VK_EXT_debug_report 1
 VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDebugReportCallbackEXT)
 
diff --git a/vulkan/libvulkan/code-generator.tmpl b/vulkan/libvulkan/code-generator.tmpl
index 33c5719..9021972 100644
--- a/vulkan/libvulkan/code-generator.tmpl
+++ b/vulkan/libvulkan/code-generator.tmpl
@@ -705,6 +705,7 @@
 VK_KHR_surface
 VK_KHR_swapchain
 VK_GOOGLE_display_timing
+VK_KHR_swapchain_front_buffered
 {{end}}
 
 
diff --git a/vulkan/libvulkan/driver_gen.cpp b/vulkan/libvulkan/driver_gen.cpp
index cfa9e30..4cc2eb5 100644
--- a/vulkan/libvulkan/driver_gen.cpp
+++ b/vulkan/libvulkan/driver_gen.cpp
@@ -93,6 +93,15 @@
     }
 }
 
+VKAPI_ATTR VkResult checkedGetSwapchainStatusKHR(VkDevice device, VkSwapchainKHR swapchain) {
+    if (GetData(device).hook_extensions[ProcHook::KHR_swapchain_front_buffered]) {
+        return GetSwapchainStatusKHR(device, swapchain);
+    } else {
+        Logger(device).Err(device, "VK_KHR_swapchain_front_buffered not enabled. vkGetSwapchainStatusKHR not executed.");
+        return VK_SUCCESS;
+    }
+}
+
 // clang-format on
 
 const ProcHook g_proc_hooks[] = {
@@ -301,6 +310,13 @@
         reinterpret_cast<PFN_vkVoidFunction>(checkedGetSwapchainImagesKHR),
     },
     {
+        "vkGetSwapchainStatusKHR",
+        ProcHook::DEVICE,
+        ProcHook::KHR_swapchain_front_buffered,
+        reinterpret_cast<PFN_vkVoidFunction>(GetSwapchainStatusKHR),
+        reinterpret_cast<PFN_vkVoidFunction>(checkedGetSwapchainStatusKHR),
+    },
+    {
         "vkQueuePresentKHR",
         ProcHook::DEVICE,
         ProcHook::KHR_swapchain,
@@ -338,6 +354,7 @@
     if (strcmp(name, "VK_KHR_surface") == 0) return ProcHook::KHR_surface;
     if (strcmp(name, "VK_KHR_swapchain") == 0) return ProcHook::KHR_swapchain;
     if (strcmp(name, "VK_GOOGLE_display_timing") == 0) return ProcHook::GOOGLE_display_timing;
+    if (strcmp(name, "VK_KHR_swapchain_front_buffered") == 0) return ProcHook::KHR_swapchain_front_buffered;
     // clang-format on
     return ProcHook::EXTENSION_UNKNOWN;
 }
diff --git a/vulkan/libvulkan/driver_gen.h b/vulkan/libvulkan/driver_gen.h
index fa81958..a137ab6 100644
--- a/vulkan/libvulkan/driver_gen.h
+++ b/vulkan/libvulkan/driver_gen.h
@@ -40,6 +40,7 @@
         KHR_surface,
         KHR_swapchain,
         GOOGLE_display_timing,
+        KHR_swapchain_front_buffered,
 
         EXTENSION_CORE,  // valid bit
         EXTENSION_COUNT,
diff --git a/vulkan/libvulkan/swapchain.cpp b/vulkan/libvulkan/swapchain.cpp
index 296be2d..66e1b0f 100644
--- a/vulkan/libvulkan/swapchain.cpp
+++ b/vulkan/libvulkan/swapchain.cpp
@@ -1077,5 +1077,16 @@
     return result;
 }
 
+VKAPI_ATTR
+VkResult GetSwapchainStatusKHR(
+    VkDevice,
+    VkSwapchainKHR) {
+    VkResult result = VK_SUCCESS;
+
+    // TODO(chrisforbes): Implement this function properly
+
+    return result;
+}
+
 }  // namespace driver
 }  // namespace vulkan
diff --git a/vulkan/libvulkan/swapchain.h b/vulkan/libvulkan/swapchain.h
index 8aac427..91d7219 100644
--- a/vulkan/libvulkan/swapchain.h
+++ b/vulkan/libvulkan/swapchain.h
@@ -36,6 +36,7 @@
 VKAPI_ATTR VkResult QueuePresentKHR(VkQueue queue, const VkPresentInfoKHR* present_info);
 VKAPI_ATTR VkResult GetRefreshCycleDurationGOOGLE(VkDevice device, VkSwapchainKHR swapchain, VkRefreshCycleDurationGOOGLE* pDisplayTimingProperties);
 VKAPI_ATTR VkResult GetPastPresentationTimingGOOGLE(VkDevice device, VkSwapchainKHR swapchain, uint32_t* pPresentationTimingCount, VkPastPresentationTimingGOOGLE* pPresentationTimings);
+VKAPI_ATTR VkResult GetSwapchainStatusKHR(VkDevice device, VkSwapchainKHR swapchain);
 // clang-format on
 
 }  // namespace driver