Include SPIR-V validation only when needed

Ensure that SPIR-V validation related headers are only included if the
respective flag was set.

Change-Id: I441bb88280527b6250d47521359b7ac64957216e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/150601
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Auto-Submit: André Cruz <andre@cabine.org>
Reviewed-by: André Cruz <andre@cabine.org>
diff --git a/src/dawn/native/vulkan/ShaderModuleVk.cpp b/src/dawn/native/vulkan/ShaderModuleVk.cpp
index 7251ba7..641303e 100644
--- a/src/dawn/native/vulkan/ShaderModuleVk.cpp
+++ b/src/dawn/native/vulkan/ShaderModuleVk.cpp
@@ -14,15 +14,12 @@
 
 #include "dawn/native/vulkan/ShaderModuleVk.h"
 
-#include <spirv-tools/libspirv.hpp>
-
 #include <map>
 #include <string>
 #include <vector>
 
 #include "dawn/native/CacheRequest.h"
 #include "dawn/native/Serializable.h"
-#include "dawn/native/SpirvValidation.h"
 #include "dawn/native/TintUtils.h"
 #include "dawn/native/vulkan/BindGroupLayoutVk.h"
 #include "dawn/native/vulkan/DeviceVk.h"
@@ -35,6 +32,10 @@
 #include "dawn/platform/tracing/TraceEvent.h"
 #include "tint/tint.h"
 
+#ifdef DAWN_ENABLE_SPIRV_VALIDATION
+#include "dawn/native/SpirvValidation.h"
+#endif
+
 namespace dawn::native::vulkan {
 
 #define COMPILED_SPIRV_MEMBERS(X)   \