Upload textures in background.

Change-Id: I365f7be9aaab793366884249cbb10e8b6f0ab0e6
diff --git a/src/com/android/gallery3d/app/AbstractGalleryActivity.java b/src/com/android/gallery3d/app/AbstractGalleryActivity.java
index 899e9bf..64c430d 100644
--- a/src/com/android/gallery3d/app/AbstractGalleryActivity.java
+++ b/src/com/android/gallery3d/app/AbstractGalleryActivity.java
@@ -33,7 +33,7 @@
 
 import com.android.gallery3d.R;
 import com.android.gallery3d.data.DataManager;
-import com.android.gallery3d.ui.BitmapPool;
+import com.android.gallery3d.data.MediaItem;
 import com.android.gallery3d.ui.GLRoot;
 import com.android.gallery3d.ui.GLRootView;
 import com.android.gallery3d.util.ThreadPool;
@@ -177,7 +177,7 @@
         } finally {
             mGLRootView.unlockRenderThread();
         }
-        BitmapPool.clear();
+        MediaItem.getMicroThumbPool().clear();
     }
 
     @Override