Merge pull request #844 from Unity-Technologies/fix/PreviewDebugFrameSettings

[HDCameraEditor] Fixed frame settings debug for camera preview

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Camera/HDCameraEditor.Handlers.cs

         {
             m_PreviewCamera.CopyFrom(c);
             EditorUtility.CopySerialized(c, m_PreviewCamera);
-            EditorUtility.CopySerialized(c.GetComponent<HDAdditionalCameraData>(), m_PreviewAdditionalCameraData);
+            var cameraData = c.GetComponent<HDAdditionalCameraData>();
+            EditorUtility.CopySerialized(cameraData, m_PreviewAdditionalCameraData);
+
+            // We need to call UpdateDirtyFrameSettings to update the dirty flags that was set in the CopySerialized call
+            m_PreviewAdditionalCameraData.UpdateDirtyFrameSettings(true, cameraData.GetFrameSettings());
+            // And then to copy the runtime frame settings
+            // So this includes the runtime frame settings properly
+            cameraData.GetFrameSettings().CopyTo(m_PreviewAdditionalCameraData.GetFrameSettings());
             m_PreviewHDCamera.Update(m_PreviewPostProcessLayer, m_PreviewAdditionalCameraData.GetFrameSettings());
 
             var previewTexture = GetPreviewTextureWithSize((int)previewSize.x, (int)previewSize.y);