code: public final void setPlaceholderTextSize(int unit,
                                               int size) {
          if (size < 0) {
              throw new IllegalArgumentException("Text size cannot be less than zero.");
          }
  
          int scaledSize = (int) TypedValue.applyDimension(unit, size, getResources().getDisplayMetrics());
          setPlaceholderTextInternal(mText, mTextColor, scaledSize, true);
      }
docs: Sets the placeholder text size.
  
  @param unit The desired dimension unit.
  @param size