Add explicit component governance build step (#22486)

- #22243
- ignore a number of artifacts/ folders that cause task warnings but don't add value
- separately, correct overuse of `$(BuildDirectory)` variable

Author: dougbu

.azure/pipelines/jobs/default-build.yml

@@ -164,7 +164,7 @@ jobs:
         displayName: Install JDK 11
       - ${{ if eq(parameters.isTestingJob, true) }}:
         - powershell: |
-            Write-Host "##vso[task.setvariable variable=SeleniumProcessTrackingFolder]$(BuildDirectory)\artifacts\tmp\selenium\"
+            Write-Host "##vso[task.setvariable variable=SeleniumProcessTrackingFolder]$(Build.SourcesDirectory)\artifacts\tmp\selenium\"
             ./eng/scripts/InstallGoogleChrome.ps1
           displayName: Install Chrome
     - ${{ if and(eq(parameters.installTar, 'true'), eq(parameters.agentOs, 'Windows')) }}:
@@ -238,13 +238,25 @@ jobs:
         continueOnError: true
         condition: always()
 
+    - ${{ if and(startsWith(parameters.jobDisplayName, 'Build:'), ne(variables['skipComponentGovernanceDetection'], 'true'), notin(variables['Build.Reason'], 'PullRequest')) }}:
+      - task: ms.vss-governance-buildtask.governance-build-task-component-detection.ComponentGovernanceComponentDetection@0
+        condition: and(succeeded(), ne(variables['CG_RAN'], 'true'))
+        displayName: 'Component Detection'
+        inputs:
+          ${{ if eq(parameters.agentOs, 'Windows') }}:
+            ignoreDirectories: '.dotnet,.packages,artifacts\log,artifacts\symbols,artifacts\tmp'
+          ${{ if ne(parameters.agentOs, 'Windows') }}:
+            ignoreDirectories: '.dotnet,.packages,artifacts/log,artifacts/symbols,artifacts/tmp'
+          sourceScanPath: $(Build.SourcesDirectory)
+          verbosity: Verbose
+
     - ${{ each artifact in parameters.artifacts }}:
       - task: PublishBuildArtifacts@1
         displayName: Upload artifacts from ${{ artifact.path }}
         condition: and(or(succeeded(), eq('${{ artifact.publishOnError }}', 'true')), or(eq(variables['system.pullrequest.isfork'], false), eq('${{ artifact.includeForks }}', 'true')))
         continueOnError: true
         inputs:
-          pathtoPublish: $(BuildDirectory)/${{ artifact.path }}
+          pathtoPublish: $(Build.SourcesDirectory)/${{ artifact.path }}
           ${{ if eq(artifact.name, '') }}:
             artifactName: artifacts-$(AgentOsName)-$(BuildConfiguration)
           ${{ if ne(artifact.name, '') }}: