Fix null paint in GradientDrawable, make default values explicit

            case LINE: {

                RectF r = mRect;

                float y = r.centerY();

                if (haveStroke) {

                    canvas.drawLine(r.left, y, r.right, y, mStrokePaint);

                }

                break;

            }

            case RING:

        public int mChangingConfigurations;

        public int mShape = RECTANGLE;

        public int mGradient = LINEAR_GRADIENT;

        public int mAngle;

        public int mAngle = 0;

        public Orientation mOrientation;

        public ColorStateList mColorStateList;

        public ColorStateList mStrokeColorStateList;

        public float[] mTempPositions; // no need to copy

        public float[] mPositions;

        public int mStrokeWidth = -1; // if >= 0 use stroking.

        public float mStrokeDashWidth;

        public float mStrokeDashGap;

        public float mRadius;    // use this if mRadiusArray is null

        public float[] mRadiusArray;

        public Rect mPadding;

        public float mStrokeDashWidth = 0.0f;

        public float mStrokeDashGap = 0.0f;

        public float mRadius = 0.0f; // use this if mRadiusArray is null

        public float[] mRadiusArray = null;

        public Rect mPadding = null;

        public int mWidth = -1;

        public int mHeight = -1;

        public float mInnerRadiusRatio = DEFAULT_INNER_RADIUS_RATIO;