Class android.support.design.widget.FloatingActionButton

The superclass changed from android.widget.ImageButton to android.support.design.widget.VisibilityAwareImageButton.

Added Methods
float getCompatElevation()  
Drawable getContentBackground()  
boolean getContentRect(Rect)  
boolean getUseCompatPadding()  
void setCompatElevation(float)  
void setUseCompatPadding(boolean)