Force-enable dithering in wide gamut & HDR

Fixes: 276779571
Test: SilkFX gradient sweep
Change-Id: I26907913feb216e43bbbc735878d12311735c3af
diff --git a/libs/hwui/renderthread/VulkanSurface.h b/libs/hwui/renderthread/VulkanSurface.h
index e2ddc6b..3b69b73 100644
--- a/libs/hwui/renderthread/VulkanSurface.h
+++ b/libs/hwui/renderthread/VulkanSurface.h
@@ -48,6 +48,8 @@
 
     void setColorSpace(sk_sp<SkColorSpace> colorSpace);
 
+    bool isBeyond8Bit() const;
+
 private:
     /*
      * All structs/methods in this private section are specifically for use by the VulkanManager