Support an --install-from-webstore command line switch

chrome/browser/extensions/startup_helper.h

Index: chrome/browser/extensions/startup_helper.h
diff --git a/chrome/browser/extensions/startup_helper.h b/chrome/browser/extensions/startup_helper.h
index f4aedc4837902e0999a42de80dd6d278fc70580b..1f88d999f71ae7a06a1f88a360eac7161c7a3d13 100644
--- a/chrome/browser/extensions/startup_helper.h
+++ b/chrome/browser/extensions/startup_helper.h
@@ -33,6 +33,11 @@ class StartupHelper : public PackExtensionJob::Client {
   // could not be started.
   bool UninstallExtension(const CommandLine& cmd_line, Profile* profile);
 
+  // Handle --install-from-webstore flag from |cmd_line| by downloading
+  // metadata from the webstore for the given id, prompting the user to
+  // confirm, and then downloading the crx and installing it.
+  bool InstallFromWebstore(const CommandLine& cmd_line, Profile* profile);
+
  private:
   scoped_refptr<PackExtensionJob> pack_job_;
   bool pack_job_succeeded_;