Drive: Mount/Unmount GoogleDrive on Files App when the file system is mounted/unmounted.

chrome/browser/chromeos/gdata/gdata_file_system_interface.h

Index: chrome/browser/chromeos/gdata/gdata_file_system_interface.h
diff --git a/chrome/browser/chromeos/gdata/gdata_file_system_interface.h b/chrome/browser/chromeos/gdata/gdata_file_system_interface.h
index b0cd9be4e41216032b436445cff37ba900567175..22b44dbe4f5049c96bbe8ac6eed342298a641dda 100644
--- a/chrome/browser/chromeos/gdata/gdata_file_system_interface.h
+++ b/chrome/browser/chromeos/gdata/gdata_file_system_interface.h
@@ -107,6 +107,11 @@ class GDataFileSystemInterface {
     // Triggered when the feed from the server is loaded.
     virtual void OnFeedFromServerLoaded() {}
 
+    // Triggered when the file system is mounted.
+    virtual void OnFileSystemMounted() {}
+    // Triggered when the file system is being unmounted.
+    virtual void OnFileSystemBeingUnmounted() {}
+
    protected:
     virtual ~Observer() {}
   };
@@ -123,6 +128,12 @@ class GDataFileSystemInterface {
   virtual void StartUpdates() = 0;
   virtual void StopUpdates() = 0;
 
+  // Notifies the file system was just mounted.
+  virtual void NotifyFileSystemMounted() = 0;
+
+  // Notifies the file system is going to be unmounted.
+  virtual void NotifyFileSystemToBeUnmounted() = 0;
+
   // Checks for updates on the server.
   virtual void CheckForUpdates() = 0;