Remove untrusted sources installation flow.

chrome/browser/android/webapk/webapk_install_service.h

Index: chrome/browser/android/webapk/webapk_install_service.h
diff --git a/chrome/browser/android/webapk/webapk_install_service.h b/chrome/browser/android/webapk/webapk_install_service.h
index 1315b0aa9513325d78f45d06e7ebc4f2b271dbb1..5e5a0f48868e25819f4d4121fa494d5c44d7e42f 100644
--- a/chrome/browser/android/webapk/webapk_install_service.h
+++ b/chrome/browser/android/webapk/webapk_install_service.h
@@ -28,8 +28,8 @@ enum class WebApkInstallResult {
   SUCCESS = 0,
   FAILURE = 1,
   // An install was initiated but it timed out. We did not get a response from
-  // Google Play (or the Android OS in the case of the "unknown sources" flow)
-  // so it is possible that the install will complete some time in the future.
+  // the install service so it is possible that the install will complete some
+  // time in the future.
   PROBABLE_FAILURE = 2
 };