Remove _NORMAL_BLEND_SRC_B keyword in decal

com.unity.render-pipelines.high-definition/HDRP/Editor/Material/Decal/DecalUI.cs

             CoreUtils.SetKeyword(material, "_COLORMAP", material.GetTexture(kBaseColorMap));
             CoreUtils.SetKeyword(material, "_NORMALMAP", material.GetTexture(kNormalMap));
             CoreUtils.SetKeyword(material, "_MASKMAP", material.GetTexture(kMaskMap)); 
-            CoreUtils.SetKeyword(material, "_NORMAL_BLEND_SRC_B", material.GetFloat(kNormalBlendSrc) == 1.0f);
-            CoreUtils.SetKeyword(material, "_MASK_BLEND_SRC_B", material.GetFloat(kMaskBlendSrc) == 1.0f);
 
             material.SetShaderPassEnabled(HDShaderPassNames.s_MeshDecalsMStr, false);
             material.SetShaderPassEnabled(HDShaderPassNames.s_MeshDecalsAOStr, false);

com.unity.render-pipelines.high-definition/HDRP/Material/Decal/Decal.shader

     #pragma shader_feature _MASKMAP
 	#pragma shader_feature _ALBEDOCONTRIBUTION
 
-	#pragma shader_feature _NORMAL_BLEND_SRC_B
-	#pragma shader_feature _MASK_BLEND_SRC_B
-
     #pragma multi_compile_instancing
     // No need to teset for DECALS_3RT we are in decal shader, so there is no OFF state
 	#pragma multi_compile _ DECALS_4RT

com.unity.render-pipelines.high-definition/HDRP/Material/Decal/DecalData.hlsl

 	surfaceData.baseColor.w = 0;	// dont blend any albedo
 #endif
 
-	float maskMapBlend;
+    // Default to _DecalBlend, if we use _NormalBlendSrc as maskmap and there is no maskmap, it mean we have 1
+	float maskMapBlend = _DecalBlend;
+
-	maskMapBlend = surfaceData.mask.z * _DecalBlend;	// store before overwriting with smoothness
+	maskMapBlend *= surfaceData.mask.z;	// store before overwriting with smoothness
-#if _MASK_BLEND_SRC_B
-	surfaceData.mask.w = maskMapBlend;
-#else
-    surfaceData.mask.w = albedoMapBlend;
-#endif
+	surfaceData.mask.w = _MaskBlendSrc ? maskMapBlend : albedoMapBlend;
 #endif
 
 	// needs to be after mask, because blend source could be in the mask map blue
 #endif
 	surfaceData.normalWS.xyz = normalWS * 0.5f + 0.5f;
 	surfaceData.HTileMask |= DBUFFERHTILEBIT_NORMAL;
-#if _NORMAL_BLEND_SRC_B
-	surfaceData.normalWS.w = maskMapBlend;
-#else
-	surfaceData.normalWS.w = albedoMapBlend;
-#endif	
+	surfaceData.normalWS.w = _NormalBlendSrc ? maskMapBlend : albedoMapBlend;
 #endif
 	surfaceData.MAOSBlend.xy = float2(surfaceData.mask.w, surfaceData.mask.w);
 }

com.unity.render-pipelines.high-definition/HDRP/Material/Decal/DecalProperties.hlsl

 TEXTURE2D(_MaskMap);
 SAMPLER(sampler_MaskMap);
 
+float _NormalBlendSrc;
+float _MaskBlendSrc;
 float _DecalBlend;
 float4 _BaseColor;
 float _DecalMeshDepthBias;