Load appropriately sized thumbnails in grid mode.

Fix a bug that is causing thumbnail size to be 80px regardless of the
display mode.  This causes larger thumbnails to be used in grid mode,
resulting in better image quality.

BUG=23385406

Change-Id: Ic62ed0de1c6326a7ccd9ca31bdead15b49c481c1

packages/DocumentsUI/src/com/android/documentsui/DirectoryFragment.java

@@ -535,8 +535,6 @@ public class DirectoryFragment extends Fragment {
 
         updateLayout(state.derivedMode);
 
-        final int thumbSize = getResources().getDimensionPixelSize(R.dimen.icon_size);
-        mThumbSize = new Point(thumbSize, thumbSize);
         mRecView.setAdapter(mAdapter);
     }