Extend the capability of SystemMonitor to support watching storage free space change

chrome/browser/system_monitor/removable_device_notifications_linux.h

Index: chrome/browser/system_monitor/removable_device_notifications_linux.h
diff --git a/chrome/browser/system_monitor/removable_device_notifications_linux.h b/chrome/browser/system_monitor/removable_device_notifications_linux.h
index cead6ed08431b6876d1cd39fc8c826f3ea95fe2e..88cf8dffa2e249c51f45ee8595aca6bd43727b6d 100644
--- a/chrome/browser/system_monitor/removable_device_notifications_linux.h
+++ b/chrome/browser/system_monitor/removable_device_notifications_linux.h
@@ -37,7 +37,8 @@ namespace chrome {
 
 class RemovableDeviceNotificationsLinux
     : public base::RefCountedThreadSafe<RemovableDeviceNotificationsLinux,
-          content::BrowserThread::DeleteOnFileThread> {
+          content::BrowserThread::DeleteOnFileThread>,
+      public base::SystemMonitor::StorageFreeSpaceDelegate {
  public:
   // Should only be called by browser start up code.  Use GetInstance() instead.
   explicit RemovableDeviceNotificationsLinux(const FilePath& path);
@@ -108,6 +109,10 @@ class RemovableDeviceNotificationsLinux
   // device SystemMonitor is notified.
   void AddNewMount(const FilePath& mount_device, const FilePath& mount_point);
 
+  // Overriden from SystemMonitor::StorageFreeSpaceDelegate.
+  virtual bool StartWatchingStorage(const FilePath::StringType& path) OVERRIDE;
+  virtual bool StopWatchingStorage(const FilePath::StringType& path) OVERRIDE;
+
   // Whether Init() has been called or not.
   bool initialized_;