add a flag to enable/disable download interception on android

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 03a8170504b43c935fb2b0b35d9634ed3506995c..6802f462a53b022110b7f72583ed77e4bfd94782 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -853,6 +853,11 @@ const FeatureEntry kFeatureEntries[] = {
      IDS_FLAGS_DOWNLOAD_RESUMPTION_DESCRIPTION,
      kOsAll,
      FEATURE_VALUE_TYPE(features::kDownloadResumption)},
+#if defined(OS_ANDROID)
+    {"enable-download-interception", IDS_FLAGS_DOWNLOAD_INTERCEPTION_NAME,
+     IDS_FLAGS_DOWNLOAD_INTERCEPTION_DESCRIPTION, kOsAndroid,
+     SINGLE_VALUE_TYPE(switches::kEnableDownloadInterception)},
+#endif
 #if defined(OS_CHROMEOS)
     {"download-notification",
      IDS_FLAGS_DOWNLOAD_NOTIFICATION_NAME,