Revert "Revert "Clear the bitmap associated with canvases.""

This reverts commit 4e012846cd.

src/com/android/launcher2/IconCache.java

@@ -104,6 +104,7 @@ public class IconCache {
         Canvas c = new Canvas(b);
         d.setBounds(0, 0, b.getWidth(), b.getHeight());
         d.draw(c);
+        c.setBitmap(null);
         return b;
     }