VFX Graph sample github button in package manager (Unity-Technologies…

…#7199)

* samples github link button

* correct folder

unity.testing.visualeffectgraph => unity.visualeffectgraph

* changelog

* Clean older versions considerations

no backport needed = clean code

* changed GUID

* Apply formatting changes

* Button text changed

Co-authored-by: noreply@unity3d.com <noreply@unity3d.com>

com.unity.visualeffectgraph/CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## [14.0.1] - 2021-12-07
 ### Added
 - New Timeline Integration which supports scrubbing
+- Samples project github link button in package manager
 
 ### Fixed
 - Creating a new VFX of the same name as an already opened VFX will reuse the existing window [Case 1382841](https://issuetracker.unity3d.com/product/unity/issues/guid/1382841/)

com.unity.visualeffectgraph/Editor/SamplesLinkPackageManagerExtension.cs

@@ -0,0 +1,52 @@
+
+using System;
+using UnityEditor.PackageManager;
+using UnityEditor.PackageManager.UI;
+using UnityEngine;
+using UnityEngine.UIElements;
+
+[UnityEditor.InitializeOnLoad]
+internal class SamplesLinkPackageManagerExtension : IPackageManagerExtension
+{
+    VisualElement rootVisualElement;
+    const string SAMPLEBUTTON_TEXT = "open VFX Graph Samples project on Github";
+    const string GITHUB_URL = "https://github.com/Unity-Technologies/VisualEffectGraph-Samples";
+    const string VFX_GRAPH_NAME = "com.unity.visualeffectgraph";
+
+    private Button samplesButton;
+    private VisualElement parent;
+
+    public VisualElement CreateExtensionUI()
+    {
+        samplesButton = new Button();
+        samplesButton.text = SAMPLEBUTTON_TEXT;
+        samplesButton.clickable.clicked += () => Application.OpenURL(GITHUB_URL);
+        return samplesButton;
+    }
+
+    static SamplesLinkPackageManagerExtension()
+    {
+        PackageManagerExtensions.RegisterExtension(new SamplesLinkPackageManagerExtension());
+    }
+
+    void IPackageManagerExtension.OnPackageSelectionChange(PackageInfo packageInfo)
+    {
+        // Prevent the button from rendering on other packages
+        if (samplesButton.parent != null)
+            parent = samplesButton.parent;
+
+        bool shouldRender = packageInfo?.name == VFX_GRAPH_NAME;
+        if (!shouldRender)
+        {
+            samplesButton.RemoveFromHierarchy();
+        }
+        else
+        {
+            parent.Add(samplesButton);
+        }
+    }
+
+    void IPackageManagerExtension.OnPackageAddedOrUpdated(PackageInfo packageInfo) { }
+
+    void IPackageManagerExtension.OnPackageRemoved(PackageInfo packageInfo) { }
+}