Updater: Add --update command flag.

Bug: 1109231
Change-Id: I48ed51576cf1a8a00a01fcdae0731076e42b176c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2340284Reviewed-by: Sorin Jianu <sorin@chromium.org>
Commit-Queue: Mila Green <milagreen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795617}

chrome/updater/constants.cc

@@ -16,6 +16,7 @@ const char kServerSwitch[] = "server";
 const char kComServiceSwitch[] = "com-service";
 const char kCrashMeSwitch[] = "crash-me";
 const char kCrashHandlerSwitch[] = "crash-handler";
+const char kUpdateSwitch[] = "update";
 const char kInstallSwitch[] = "install";
 const char kUninstallSwitch[] = "uninstall";
 const char kSystemSwitch[] = "system";

chrome/updater/constants.h

@@ -53,6 +53,9 @@ extern const char kCrashMeSwitch[];
 // Runs as the Crashpad handler.
 extern const char kCrashHandlerSwitch[];
 
+// Updates the updater.
+extern const char kUpdateSwitch[];
+
 // Installs the updater.
 extern const char kInstallSwitch[];
 

chrome/updater/updater.cc

@@ -99,6 +99,11 @@ int HandleUpdaterCommands(const base::CommandLine* command_line) {
 #endif
   }
 
+#if defined(OS_MAC)
+  if (command_line->HasSwitch(kUpdateSwitch))
+    return MakeAppInstall()->Run();
+#endif  // OS_MAC
+
 #if defined(OS_WIN)
   if (command_line->HasSwitch(kComServiceSwitch))
     return ServiceMain::RunComService(command_line);