Cleanup: Remove unnecessary property: VolumeList.currentVolume_

This property can be removed. This patch also fixes a small bug on changing the selection on the list.

BUG=none
TEST=manual
R=mtomasz@chromium.org

Review URL: https://codereview.chromium.org/22167002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@215817 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/file_manager/js/volume_list.js

@@ -186,8 +186,6 @@ VolumeList.prototype.decorate = function(directoryModel, pinnedFolderModel) {
       'change', this.onSelectionChange_.bind(this));
   this.selectionModel.addEventListener(
       'beforeChange', this.onBeforeSelectionChange_.bind(this));
-  this.currentVolume_ = null;
-
 
   this.scrollBar_ = new ScrollBar();
   this.scrollBar_.initialize(this.parentNode, this);
@@ -314,11 +312,14 @@ VolumeList.prototype.selectByIndex = function(index) {
     return false;
 
   var newPath = this.dataModel.item(index);
-  if (!newPath || this.currentVolume_ == newPath)
+  if (!newPath)
+    return false;
+
+  // Prevents double-moving to the current directory.
+  if (this.directoryModel_.getCurrentDirEntry().fullPath == newPath)
     return false;
 
-  this.currentVolume_ = newPath;
-  this.directoryModel_.changeDirectory(this.currentVolume_);
+  this.directoryModel_.changeDirectory(newPath);
   return true;
 };
 
@@ -355,10 +356,6 @@ VolumeList.prototype.onCurrentDirectoryChanged_ = function(event) {
   var path = event.newDirEntry.fullPath || this.dataModel.getCurrentDirPath();
   var newRootPath = PathUtil.getRootPath(path);
 
-  // Sets |this.currentVolume_| in advance to prevent |onSelectionChange_()|
-  // from calling |DirectoryModel.ChangeDirectory()| again.
-  this.currentVolume_ = newRootPath;
-
   // Synchronizes the volume list selection with the current directory, after
   // it is changed outside of the volume list.