borrow relevant parts of AOSP commit dbee9bb342cdfaa5155b1918f90262c05e2464cb

Our SVG-based VectorDrawable implementation still relies on `getDefaultColor`
but exceptions are no longer thrown when parsing VectorDrawable xml files
which use gradients as colors.

src/api-impl/android/graphics/Shader.java

@@ -8,5 +8,11 @@ public class Shader {
 		REPEAT
 	}
 
+	protected void init(long ni) {
+	}
+
 	public void setLocalMatrix(Matrix matrix) {}
+
+
+	protected void copyLocalMatrix(Shader dest) {}
 }

src/api-impl/android/graphics/SweepGradient.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.graphics;
+
+public class SweepGradient extends Shader {
+
+	private static final int TYPE_COLORS_AND_POSITIONS = 1;
+	private static final int TYPE_COLOR_START_AND_COLOR_END = 2;
+
+	/**
+	 * Type of the LinearGradient: can be either TYPE_COLORS_AND_POSITIONS or
+	 * TYPE_COLOR_START_AND_COLOR_END.
+	 */
+	private int mType;
+
+	private float mCx;
+	private float mCy;
+	private int[] mColors;
+	private float[] mPositions;
+	private int mColor0;
+	private int mColor1;
+
+	/**
+	 * A subclass of Shader that draws a sweep gradient around a center point.
+	 *
+	 * @param cx       The x-coordinate of the center
+	 * @param cy       The y-coordinate of the center
+	 * @param colors   The colors to be distributed between around the center.
+	 *                 There must be at least 2 colors in the array.
+	 * @param positions May be NULL. The relative position of
+	 *                 each corresponding color in the colors array, beginning
+	 *                 with 0 and ending with 1.0. If the values are not
+	 *                 monotonic, the drawing may produce unexpected results.
+	 *                 If positions is NULL, then the colors are automatically
+	 *                 spaced evenly.
+	 */
+	public SweepGradient(float cx, float cy,
+			     int colors[], float positions[]) {
+		if (colors.length < 2) {
+			throw new IllegalArgumentException("needs >= 2 number of colors");
+		}
+		if (positions != null && colors.length != positions.length) {
+			throw new IllegalArgumentException(
+			    "color and position arrays must be of equal length");
+		}
+		mType = TYPE_COLORS_AND_POSITIONS;
+		mCx = cx;
+		mCy = cy;
+		mColors = colors;
+		mPositions = positions;
+		init(nativeCreate1(cx, cy, colors, positions));
+	}
+
+	/**
+	 * A subclass of Shader that draws a sweep gradient around a center point.
+	 *
+	 * @param cx       The x-coordinate of the center
+	 * @param cy       The y-coordinate of the center
+	 * @param color0   The color to use at the start of the sweep
+	 * @param color1   The color to use at the end of the sweep
+	 */
+	public SweepGradient(float cx, float cy, int color0, int color1) {
+		mType = TYPE_COLOR_START_AND_COLOR_END;
+		mCx = cx;
+		mCy = cy;
+		mColor0 = color0;
+		mColor1 = color1;
+		init(nativeCreate2(cx, cy, color0, color1));
+	}
+
+	/**
+	 * @hide
+	 */
+	//@Override
+	protected Shader copy() {
+		final SweepGradient copy;
+		switch (mType) {
+			case TYPE_COLORS_AND_POSITIONS:
+				copy = new SweepGradient(mCx, mCy, mColors.clone(),
+							 mPositions != null ? mPositions.clone() : null);
+				break;
+			case TYPE_COLOR_START_AND_COLOR_END:
+				copy = new SweepGradient(mCx, mCy, mColor0, mColor1);
+				break;
+			default:
+				throw new IllegalArgumentException("SweepGradient should be created with either "
+								   +
+								   "colors and positions or start color and end color");
+		}
+		copyLocalMatrix(copy);
+		return copy;
+	}
+
+	private static native long nativeCreate1(float x, float y, int colors[], float positions[]);
+	private static native long nativeCreate2(float x, float y, int color0, int color1);
+}