Add a component installer for Portable NaCl. Registration of installer is

chrome/browser/component_updater/component_updater_configurator.cc

Index: chrome/browser/component_updater/component_updater_configurator.cc
diff --git a/chrome/browser/component_updater/component_updater_configurator.cc b/chrome/browser/component_updater/component_updater_configurator.cc
index 7588192c93f63371dd6818b90c82e91f90b82797..5f93d7ac9e0eb042ddef245b0fad40eb2a09358d 100644
--- a/chrome/browser/component_updater/component_updater_configurator.cc
+++ b/chrome/browser/component_updater/component_updater_configurator.cc
@@ -110,6 +110,7 @@ class ChromeConfigurator : public ComponentUpdateService::Configurator {
   std::string extra_info_;
   bool fast_update_;
   bool out_of_process_;
+  GURL app_update_url_;
 };
 
 ChromeConfigurator::ChromeConfigurator(const CommandLine* cmdline,
@@ -122,6 +123,15 @@ ChromeConfigurator::ChromeConfigurator(const CommandLine* cmdline,
       ",", &debug_values);
   fast_update_ = HasDebugValue(debug_values, kDebugFastUpdate);
   out_of_process_ = HasDebugValue(debug_values, kDebugOutOfProcess);
+
+  // Allow switch to override update URL (piggyback on AppsGalleryUpdateURL).
+  if (cmdline->HasSwitch(switches::kAppsGalleryUpdateURL)) {
+    app_update_url_ =
+        GURL(cmdline->GetSwitchValueASCII(switches::kAppsGalleryUpdateURL));
+  } else {
+    app_update_url_ = GURL("http://clients2.google.com/service/update2/crx");
+  }
+
   // Make the extra request params, they are necessary so omaha does
   // not deliver components that are going to be rejected at install time.
   extra_info_ += chrome::VersionInfo().Version();
@@ -146,7 +156,7 @@ int ChromeConfigurator::MinimumReCheckWait() {
 }
 
 GURL ChromeConfigurator::UpdateUrl() {
-  return GURL("http://clients2.google.com/service/update2/crx");
+  return app_update_url_;
 }
 
 const char* ChromeConfigurator::ExtraRequestParams() {