Add a flag to specify whether to show ARC Files app in launcher.

components/arc/arc_features.cc

Index: components/arc/arc_features.cc
diff --git a/components/arc/arc_features.cc b/components/arc/arc_features.cc
index 5e3f68ffac29945a791fcc84a2c1cee4a035e462..e5db91b0710a232f4227cc7e5f0f386de1a11363 100644
--- a/components/arc/arc_features.cc
+++ b/components/arc/arc_features.cc
@@ -17,4 +17,9 @@ const base::Feature kBootCompletedBroadcastFeature {
     "ArcBootCompletedBroadcast", base::FEATURE_ENABLED_BY_DEFAULT
 };
 
+// Controls whether we show Arc Files app in Chrome launcher.
+const base::Feature kShowArcFilesAppFeature {
+    "ShowArcFilesApp", base::FEATURE_DISABLED_BY_DEFAULT
+};
+
 }  // namespace arc