Fix paths and imports for HD sub-shader

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/ShaderGraph/HDPBRSubShader.cs

 using System.IO;
 using System.Linq;
 using UnityEditor.Graphing;
-
+using UnityEditor.ShaderGraph;
-namespace UnityEditor.ShaderGraph
+namespace UnityEditor.Experimental.Rendering.HDPipeline
 {
     public class HDPBRSubShader : IPBRSubShader
     {
 
         private static bool GenerateShaderPass(PBRMasterNode masterNode, Pass pass, GenerationMode mode, SurfaceMaterialOptions materialOptions, ShaderGenerator result)
         {
-            var templateLocation = ShaderGenerator.GetTemplatePath(pass.TemplateName);
+            var templateLocation = Path.Combine(Path.Combine(Path.Combine(HDEditorUtils.GetHDRenderPipelinePath(), "Editor"), "ShaderGraph"), pass.TemplateName);
             if (!File.Exists(templateLocation))
             {
                 // TODO: produce error here
             return subShader.GetShaderString(0);
         }
     }
-}
+}

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/ShaderGraph/HDSubShaderUtilities.cs

 using UnityEngine;              // Vector3,4
 using UnityEditor.ShaderGraph;
 
-namespace UnityEditor.ShaderGraph
+namespace UnityEditor.Experimental.Rendering.HDPipeline
 {
     public static class HDRPShaderStructs
     {
             return materialOptions;
         }
     }
-}
+}

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/ShaderGraph/HDUnlitSubShader.cs

 using System.IO;
 using System.Linq;
 using UnityEditor.Graphing;
+using UnityEditor.ShaderGraph;
-namespace UnityEditor.ShaderGraph
+namespace UnityEditor.Experimental.Rendering.HDPipeline
 {
 //    [Serializable] ??
     public class HDUnlitSubShader : IUnlitSubShader
             return subShader.GetShaderString(0);
         }
     }
-}
+}

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/com.unity.render-pipelines.high-definition.Editor.asmdef

         "com.unity.render-pipelines.core.Editor",
         "com.unity.render-pipelines.high-definition.Runtime",
         "com.unity.postprocessing.Runtime",
-        "com.unity.postprocessing.Editor"
+        "com.unity.postprocessing.Editor",
+        "Unity.ShaderGraph.Editor"
     ],
     "optionalUnityReferences": [],
     "includePlatforms": [

ScriptableRenderPipeline/HDRenderPipeline/sub-package.json

 	"description": "HD Render Pipeline for Unity.",
     "subDependencies": [
         "com.unity.render-pipelines.core"
-    ]
+    ],
+    "dependencies": {
+        "com.unity.shadergraph": "0.1.19"
+    }
 }