Make UpgradeDetector listen to VariationsService changes.

chrome/browser/upgrade_detector_impl.h

Index: chrome/browser/upgrade_detector_impl.h
===================================================================
--- chrome/browser/upgrade_detector_impl.h	(revision 286992)
+++ chrome/browser/upgrade_detector_impl.h	(working copy)
@@ -8,11 +8,14 @@
 #include "base/memory/weak_ptr.h"
 #include "base/timer/timer.h"
 #include "base/version.h"
+#include "chrome/browser/metrics/variations/variations_service.h"
 #include "chrome/browser/upgrade_detector.h"
 
 template <typename T> struct DefaultSingletonTraits;
 
-class UpgradeDetectorImpl : public UpgradeDetector {
+class UpgradeDetectorImpl :
+    public UpgradeDetector,
+    public chrome_variations::VariationsService::Observer {
  public:
   virtual ~UpgradeDetectorImpl();
 
@@ -24,17 +27,30 @@
   // Returns the singleton instance.
   static UpgradeDetectorImpl* GetInstance();
 
+ protected:
+  UpgradeDetectorImpl();
+
+  // chrome_variations::VariationsService::Observer:
+  virtual void OnExperimentChangesDetected(Severity severity) OVERRIDE;
+
+  // Trigger an "on upgrade" notification based on the specified |time_passed|
+  // interval. Exposed as protected for testing.
+  void NotifyOnUpgradeWithTimePassed(base::TimeDelta time_passed);
+
  private:
   friend struct DefaultSingletonTraits<UpgradeDetectorImpl>;
 
-  UpgradeDetectorImpl();
-
   // Start the timer that will call |CheckForUpgrade()|.
   void StartTimerForUpgradeCheck();
 
   // Launches a task on the file thread to check if we have the latest version.
   void CheckForUpgrade();
 
+  // Starts the upgrade notification timer that will check periodically whether
+  // enough time has elapsed to update the severity (which maps to visual
+  // badging) of the notification.
+  void StartUpgradeNotificationTimer();
+
   // Sends out a notification and starts a one shot timer to wait until
   // notifying the user.
   void UpgradeDetected(UpgradeAvailable upgrade_available);
@@ -74,6 +90,10 @@
   // True if auto update is turned on.
   bool is_auto_update_enabled_;
 
+  // When the upgrade was detected - either a software update or a variations
+  // update, whichever happened first.
+  base::Time upgrade_detected_time_;
+
   // The date the binaries were built.
   base::Time build_date_;