ShapeDrawable.inflateTag() handles the 'padding' tag with the standard
attributes android:left, etc. The attribute values for these standard
attributes should be dimension specifications, e.g. '4dp'.
ShapeDrawable.inflateTag() was wrongly parsing the attribute values as plain
integers.
DrawableContainerState.mDrawables is an array which may be only partially
filled, as can be seen in the constructor and the addChild() method.
DrawableContainer.mutate() wrongly assumed that the array does not contain
null references.
The mColors member can be null, as can be seen in
GradientDrawable.setSolidColor() or the plain constructor. In that case, an NPE
will be thrown on attempts to derive a new GradientDrawable from the instance
using the private constructor GradientDrawable(GradientDrawable).
The problem also occurs when inflating a GradientDrawable from XML without
defining the start, center and end colors and then calling mutate() on the
instance.
