add new gclient_cache folder to cleanup

Library/Homebrew/cleanup.rb

@@ -9,7 +9,7 @@ module CleanupRefinement
     end
 
     def nested_cache?
-      directory? && ["glide_home", "java_cache", "npm_cache"].include?(basename.to_s)
+      directory? && %w[glide_home java_cache npm_cache gclient_cache].include?(basename.to_s)
     end
 
     def prune?(days)

Library/Homebrew/test/cleanup_spec.rb

@@ -197,6 +197,15 @@ describe Homebrew::Cleanup do
       expect(npm_cache).not_to exist
     end
 
+    it "cleans up 'gclient_cache'" do
+      gclient_cache = (HOMEBREW_CACHE/"gclient_cache")
+      gclient_cache.mkpath
+
+      subject.cleanup_cache
+
+      expect(gclient_cache).not_to exist
+    end
+
     it "cleans up all files and directories" do
       git = (HOMEBREW_CACHE/"gist--git")
       gist = (HOMEBREW_CACHE/"gist")