Revert "Remove $(AndroidWorkloadExtendsElement)"

This reverts commit 2d07a35.

Author: jonathanpeppers

build-tools/create-packs/ConfigureLocalWorkload.targets

@@ -47,6 +47,34 @@
     <Exec Command="&quot;$(DotNetPreviewTool)&quot; pack @(_PackProps, ' ') &quot;$(XamarinAndroidSourcePath)src\Microsoft.Android.Templates\Microsoft.Android.Templates.csproj&quot;" />
   </Target>
 
+  <UsingTask TaskName="GetAndroidWorkloadExtends" TaskFactory="RoslynCodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll">
+    <ParameterGroup>
+      <JsonFilePath ParameterType="System.String" Required="true" />
+      <ExtendsElement Output="true" ParameterType="System.String" />
+    </ParameterGroup>
+    <Task>
+      <Using Namespace="System" />
+      <Using Namespace="System.IO" />
+      <Code Type="Fragment" Language="cs">
+        <![CDATA[
+        var jsonContent = File.ReadAllText(JsonFilePath);
+        var startElement = "\"extends\" : [";
+        var startIndex = jsonContent.IndexOf(startElement);
+        var endIndex = jsonContent.IndexOf("]");
+        if (startIndex != -1) {
+            startIndex += startElement.Length;
+            endIndex = jsonContent.IndexOf("]", startIndex);
+            if (endIndex != -1) {
+                ExtendsElement = jsonContent.Substring(startIndex, endIndex - startIndex)?.Trim();
+            }
+        }
+        if (startIndex == -1 || endIndex == -1 || string.IsNullOrEmpty(ExtendsElement))
+            Log.LogError($"Failed to find extends element in workload json '{JsonFilePath}'");
+        ]]>
+      </Code>
+    </Task>
+  </UsingTask>
+
   <Target Name="InstallManifestAndDependencies"
       DependsOnTargets="_GetDefaultPackageVersion">
     <PropertyGroup>
@@ -62,15 +90,20 @@
         Targets="_GenerateXAWorkloadContent"
     />
 
+    <GetAndroidWorkloadExtends JsonFilePath="$(_LocalAndroidManifestFolder)WorkloadManifest.json">
+      <Output TaskParameter="ExtendsElement" PropertyName="AndroidWorkloadExtendsElement" />
+    </GetAndroidWorkloadExtends>
+
     <PropertyGroup>
       <_EmptyWorkloadJsonContent>
 <![CDATA[
-{"version": "0.0.1", "workloads": { "android-deps": { "extends" : [ "microsoft-net-runtime-android" ] } } }
+{"version": "0.0.1", "workloads": { "android-deps": { "extends" : [ $(AndroidWorkloadExtendsElement) ] } } }
 ]]>
       </_EmptyWorkloadJsonContent>
     </PropertyGroup>
 
     <!-- Create empty workload to install dotnet/runtime dependencies, and then clean up the workload and metadata files from install -->
+    <Error Condition=" '$(AndroidWorkloadExtendsElement)' == '' " Text="Failed to find extends element in workload json" />
     <MakeDir Directories="$(_EmptyWorkloadDir)" />
     <WriteLinesToFile
         File="$(_EmptyWorkloadDir)WorkloadManifest.json"