[fsp] Add requestUnmount() method together with the request manager.

chrome/browser/chromeos/file_manager/volume_manager.h

Index: chrome/browser/chromeos/file_manager/volume_manager.h
diff --git a/chrome/browser/chromeos/file_manager/volume_manager.h b/chrome/browser/chromeos/file_manager/volume_manager.h
index bbbdfa7356f93ae22b068cc2e775272d452fc74b..068f3cff1886fb5d9c58e602d81ea7dbd263eed7 100644
--- a/chrome/browser/chromeos/file_manager/volume_manager.h
+++ b/chrome/browser/chromeos/file_manager/volume_manager.h
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
@@ -56,6 +57,9 @@ struct VolumeInfo {
   VolumeInfo();
   ~VolumeInfo();
 
+  // The ID for provided file system. If other type, then undefined.
+  int file_system_id;
+
   // The ID of the volume.
   std::string volume_id;
 
@@ -169,12 +173,12 @@ class VolumeManager : public KeyedService,
       const std::string& device_path) OVERRIDE;
 
   // chromeos::file_system_provider::Observer overrides.
-  virtual void OnProvidedFileSystemRegistered(
-      const chromeos::file_system_provider::ProvidedFileSystem& file_system)
-      OVERRIDE;
-  virtual void OnProvidedFileSystemUnregistered(
-      const chromeos::file_system_provider::ProvidedFileSystem& file_system)
-      OVERRIDE;
+  virtual void OnProvidedFileSystemMount(
+      const chromeos::file_system_provider::ProvidedFileSystem& file_system,
+      base::File::Error error) OVERRIDE;
+  virtual void OnProvidedFileSystemUnmount(
+      const chromeos::file_system_provider::ProvidedFileSystem& file_system,
+      base::File::Error error) OVERRIDE;
 
   // Called on change to kExternalStorageDisabled pref.
   void OnExternalStorageDisabledChanged();