Disable ACTION_BOOT_COMPLETED event for 3rd party apps.

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 4c7315bcd75151acdd16cd3c955bcf0f98162ba3..f3d96580fb0a9e76bad53281783babb1a3dca16a 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -90,6 +90,7 @@
 
 #if defined(OS_CHROMEOS)
 #include "chromeos/chromeos_switches.h"
+#include "components/arc/arc_features.h"
 #include "third_party/cros_system_api/switches/chrome_switches.h"
 #endif
 
@@ -2102,6 +2103,12 @@ const FeatureEntry kFeatureEntries[] = {
     {"material-security-verbose", IDS_FLAGS_MATERIAL_SECURITY_VERBOSE_NAME,
      IDS_FLAGS_MATERIAL_SECURITY_VERBOSE_DESCRIPTION, kOsDesktop,
      MULTI_VALUE_TYPE(kSecurityVerboseChoices)},
+#if defined(OS_CHROMEOS)
+    {"arc-boot-completed-broadcast",
+     IDS_FLAGS_ARC_BOOT_COMPLETED,
+     IDS_FLAGS_ARC_BOOT_COMPLETED_DESCRIPTION, kOsCrOS,
+     FEATURE_VALUE_TYPE(arc::kBootCompletedBroadcastFeature)},
+#endif
     // NOTE: Adding new command-line switches requires adding corresponding
     // entries to enum "LoginCustomFlags" in histograms.xml. See note in
     // histograms.xml and don't forget to run AboutFlagsHistogramTest unit test.