Remove unused library dawn_vulkan_headers

- dawn/native/CMakeLists.txt uses Vulkan-Headers

Change-Id: I914034e63358de8f0f0b591c2e612b00e3d1888e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/194905
Auto-Submit: Jaswant Panchumarti <jaswant.panchumarti@kitware.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: dan sinclair <dsinclair@chromium.org>
diff --git a/third_party/CMakeLists.txt b/third_party/CMakeLists.txt
index d60b74f..b95f575 100644
--- a/third_party/CMakeLists.txt
+++ b/third_party/CMakeLists.txt
@@ -116,25 +116,11 @@
     target_include_directories(dawn_khronos_platform INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}/khronos/EGL-Registry/api")
 endif()
 
-if (DAWN_ENABLE_VULKAN)
-    if (NOT TARGET Vulkan-Headers)
-        message(STATUS "Dawn: using Vulkan-Headers at ${DAWN_VULKAN_HEADERS_DIR}")
+if (NOT TARGET Vulkan-Headers AND DAWN_ENABLE_VULKAN)
+    message(STATUS "Dawn: using Vulkan-Headers at ${DAWN_VULKAN_HEADERS_DIR}")
 
-        set(VULKAN_HEADERS_ENABLE_MODULE OFF)
-        add_subdirectory(${DAWN_VULKAN_HEADERS_DIR} "${CMAKE_CURRENT_BINARY_DIR}/vulkan-headers")
-    endif()
-
-    # Header-only library for Vulkan headers
-    add_library(dawn_vulkan_headers INTERFACE)
-    target_sources(dawn_vulkan_headers INTERFACE
-        "${CMAKE_CURRENT_SOURCE_DIR}/khronos/vulkan/vk_icd.h"
-        "${CMAKE_CURRENT_SOURCE_DIR}/khronos/vulkan/vk_layer.h"
-        "${CMAKE_CURRENT_SOURCE_DIR}/khronos/vulkan/vk_platform.h"
-        "${CMAKE_CURRENT_SOURCE_DIR}/khronos/vulkan/vk_sdk_platform.h"
-        "${CMAKE_CURRENT_SOURCE_DIR}/khronos/vulkan/vulkan.h"
-        "${CMAKE_CURRENT_SOURCE_DIR}/khronos/vulkan/vulkan_core.h"
-    )
-    target_include_directories(dawn_vulkan_headers INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}/khronos")
+    set(VULKAN_HEADERS_ENABLE_MODULE OFF)
+    add_subdirectory(${DAWN_VULKAN_HEADERS_DIR} "${CMAKE_CURRENT_BINARY_DIR}/vulkan-headers")
 endif()
 
 if (DAWN_ENABLE_SWIFTSHADER AND NOT TARGET vk_swiftshader)