Consistently use notifications from component updater w/ on-demand PNaCl.

chrome/browser/component_updater/pnacl/pnacl_updater_observer.cc

Index: chrome/browser/component_updater/pnacl/pnacl_updater_observer.cc
diff --git a/chrome/browser/component_updater/pnacl/pnacl_updater_observer.cc b/chrome/browser/component_updater/pnacl/pnacl_updater_observer.cc
index 2a3a6fa891914eb5e626177235f414a1f71fce20..e036e989c4bfbea56f709640f7f229c0bf1a54c0 100644
--- a/chrome/browser/component_updater/pnacl/pnacl_updater_observer.cc
+++ b/chrome/browser/component_updater/pnacl/pnacl_updater_observer.cc
@@ -9,23 +9,48 @@
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/notification_service.h"
 
-PnaclUpdaterObserver::PnaclUpdaterObserver(
-    PnaclComponentInstaller* installer) : pnacl_installer_(installer) {
-  registrar_.Add(this,
-                 chrome::NOTIFICATION_COMPONENT_UPDATER_SLEEPING,
-                 content::NotificationService::AllSources());
+PnaclUpdaterObserver::PnaclUpdaterObserver(PnaclComponentInstaller* installer)
+    : pnacl_installer_(installer) {}
+
+PnaclUpdaterObserver::~PnaclUpdaterObserver() {}
+
+void PnaclUpdaterObserver::EnsureObserving() {
+  if (registrar_.IsEmpty()) {
+    registrar_.Add(this,
+                   chrome::NOTIFICATION_COMPONENT_UPDATE_READY,
+                   content::NotificationService::AllSources());
+    registrar_.Add(this,
+                   chrome::NOTIFICATION_COMPONENT_UPDATER_SLEEPING,
+                   content::NotificationService::AllSources());
+  }
 }
 
-PnaclUpdaterObserver::~PnaclUpdaterObserver() { }
+void PnaclUpdaterObserver::StopObserving() {
+  registrar_.RemoveAll();
+}
 
 void PnaclUpdaterObserver::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
+
+  if (type == chrome::NOTIFICATION_COMPONENT_UPDATE_READY) {
+    // If the component updater says there is an UPDATE_READY w/ source
+    // being the PNaCl ID, then installation is handed off to the PNaCl
+    // installer and we can stop observing.
+    if (pnacl_installer_->cus()->IsUpdateNotificationForComponent(
+            source, pnacl_installer_->GetCrxComponent())) {
+      StopObserving();
+    }
+    return;
+  }
+
   if (type == chrome::NOTIFICATION_COMPONENT_UPDATER_SLEEPING) {
-    // If the component updater sleeps before a NotifyInstallSuccess,
-    // then requests for installs were likely skipped, or an error occurred.
+    // If the component updater sleeps before an UPDATE_READY for this
+    // component, then requests for installs were likely skipped,
+    // an error occurred, or the component is already up to date.
     pnacl_installer_->NotifyInstallError();
+    StopObserving();
     return;
   }
 }