No longer start BG mode until a BackgroundContents is loaded

chrome/browser/background/background_contents_service.h

Index: chrome/browser/background/background_contents_service.h
diff --git a/chrome/browser/background/background_contents_service.h b/chrome/browser/background/background_contents_service.h
index 10b7677bf1929d496c77136a8ebb9e5113f8c398..7232cce9baae84913b5cf7552b7f20fd9ba22c4a 100644
--- a/chrome/browser/background/background_contents_service.h
+++ b/chrome/browser/background/background_contents_service.h
@@ -53,6 +53,12 @@ class BackgroundContentsService : private content::NotificationObserver,
   // or NULL if none.
   BackgroundContents* GetAppBackgroundContents(const string16& appid);
 
+  // Returns true if there's a registered BackgroundContents for this app. It
+  // is possible for this routine to return true when GetAppBackgroundContents()
+  // returns false, if the BackgroundContents closed due to the render process
+  // crashing.
+  bool HasRegisteredBackgroundContents(const string16& appid);

[Mihai Parparita -not on Chrome, 2012/05/03 00:54:11]

Beyond the scope of this CL, but why are app IDs stored as string16 here? In all
other cases, extension/app IDs are stored as std::strings.

[Andrew T Wilson (Slow), 2012/05/03 07:42:56]

Yeah, at one point a few years back when writing this, we (chrome team) were
going to convert to using string16 everywhere, and new APIs were supposed to use
string16. So that's why we added this as string16 - not sure if this is still a
goal or not.

+
   // Returns all currently opened BackgroundContents (used by the task manager).
   std::vector<BackgroundContents*> GetBackgroundContents() const;
 
@@ -152,6 +158,11 @@ class BackgroundContentsService : private content::NotificationObserver,
   // Returns true if this BackgroundContents is in the contents_list_.
   bool IsTracked(BackgroundContents* contents) const;
 
+  // Sends out a notification when our association of background contents with
+  // apps may have changed (used by BackgroundApplicationListModel to update the
+  // set of background apps as new background contents are opened/closed).
+  void SendChangeNotification(Profile* profile);
+
   // PrefService used to store list of background pages (or NULL if this is
   // running under an incognito profile).
   PrefService* prefs_;