"mach clean" cleans uwp artifacts

.gitignore

@@ -55,37 +55,7 @@ support/hololens/ServoApp/ARM64/
 support/hololens/ServoApp/Generated\ Files
 support/hololens/ServoApp/BundleArtifacts/
 support/hololens/ServoApp/support/
-
-# Ignore thumbnails created by Windows
-support/hololens/ServoApp/Thumbs.db
-
-# Ignore files built by Visual Studio
-support/hololens/ServoApp/*.obj
-support/hololens/ServoApp/*.exe
-support/hololens/ServoApp/*.pdb
-support/hololens/ServoApp/*.user
-support/hololens/ServoApp/*.aps
-support/hololens/ServoApp/*.pch
-support/hololens/ServoApp/*.vspscc
-support/hololens/ServoApp/*_i.c
-support/hololens/ServoApp/*_p.c
-support/hololens/ServoApp/*.ncb
-support/hololens/ServoApp/*.suo
-support/hololens/ServoApp/*.tlb
-support/hololens/ServoApp/*.tlh
-support/hololens/ServoApp/*.bak
-support/hololens/ServoApp/*.cache
-support/hololens/ServoApp/*.ilk
-support/hololens/ServoApp/*.log
-support/hololens/ServoApp/[Bb]in
-support/hololens/ServoApp/[Dd]ebug*/
-support/hololens/ServoApp/*.lib
-support/hololens/ServoApp/*.sbr
-support/hololens/ServoApp/obj/
-support/hololens/ServoApp/[Rr]elease*/
-support/hololens/ServoApp/_ReSharper*/
-support/hololens/ServoApp/[Tt]est[Rr]esult*
-support/hololens/.vs/
-
-# Nuget packages folder
+support/hololens/ServoApp/Debug/
+support/hololens/ServoApp/Release/
 support/hololens/packages/
+support/hololens/.vs/

python/servo/build_commands.py

@@ -741,6 +741,26 @@ def clean(self, manifest_path=None, params=[], verbose=False):
             print('Removing virtualenv directory: %s' % virtualenv_path)
             shutil.rmtree(virtualenv_path)
 
+        uwp_artifacts = [
+            "support/hololens/x64/",
+            "support/hololens/ARM/",
+            "support/hololens/ARM64/",
+            "support/hololens/ServoApp/x64/",
+            "support/hololens/ServoApp/ARM/",
+            "support/hololens/ServoApp/ARM64/",
+            "support/hololens/ServoApp/Generated Files/",
+            "support/hololens/ServoApp/BundleArtifacts/",
+            "support/hololens/ServoApp/support/",
+            "support/hololens/ServoApp/Debug/",
+            "support/hololens/ServoApp/Release/",
+            "support/hololens/packages/",
+        ]
+
+        for uwp_artifact in uwp_artifacts:
+            dir_path = path.join(self.get_top_dir(), uwp_artifact)
+            if path.exists(dir_path):
+                shutil.rmtree(dir_path)
+
         opts = ["--manifest-path", manifest_path or path.join(self.context.topdir, "Cargo.toml")]
         if verbose:
             opts += ["-v"]