Extract from <android_sdk>/extras/android/support/v4/src/honeycomb/android/support/v4/app/ActionBarDrawerToggleHoneycomb.java

ActionBarDrawerToggleHoneycomb.java

/**
 * This class encapsulates some awful hacks.
 *
 * Before JB-MR2 (API 18) it was not possible to change the home-as-up indicator glyph
 * in an action bar without some really gross hacks. Since the MR2 SDK is not published as of
 * this writing, the new API is accessed via reflection here if available.
 */
class ActionBarDrawerToggleHoneycomb {
    private static final String TAG = "ActionBarDrawerToggleHoneycomb";