Fixes a typo: use the default image if the extension doesn't have icon.

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 70e93187f79cdb9993ee1dc694659a217057e3eb..66437b3b0ac9a0b81956b2db3ef70d348388c111 100644
--- a/chrome/browser/background/background_contents_service.h
+++ b/chrome/browser/background/background_contents_service.h
@@ -61,6 +61,15 @@ class BackgroundContentsService : private content::NotificationObserver,
   static void SetRestartDelayForForceInstalledAppsAndExtensionsForTesting(
       int restart_delay_in_ms);
 
+  // Get the crash notification's id for the extension.
+  static std::string GetNotificationIdForExtensionForTesting(
+      const std::string& extension_id);
+
+  // Show a popup notification balloon with a crash message for a given app/
+  // extension.
+  static void ShowBalloonForTesting(const extensions::Extension* extension,
+                                    Profile* profile);
+
   // Returns the BackgroundContents associated with the passed application id,
   // or NULL if none.
   BackgroundContents* GetAppBackgroundContents(const base::string16& appid);