implement ColorFilter in GskCanvas

This is needed to make icons follow night mode setting

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

@@ -35,7 +35,11 @@ public class GskCanvas extends Canvas {
 
 	@Override
 	public void drawBitmap(Bitmap bitmap, Rect src, Rect dst, Paint paint) {
-		native_drawBitmap(snapshot, bitmap.pixbuf, dst.left, dst.top, dst.width(), dst.height());
+		int color = 0;
+		if (paint != null && paint.colorFilter instanceof PorterDuffColorFilter) {
+			color = ((PorterDuffColorFilter) paint.colorFilter).getColor();
+		}
+		native_drawBitmap(snapshot, bitmap.pixbuf, dst.left, dst.top, dst.width(), dst.height(), color);
 	}
 
 	@Override
@@ -70,5 +74,5 @@ public class GskCanvas extends Canvas {
 		drawBitmap(bitmap, src, dst, paint);
 	}
 
-	protected native void native_drawBitmap(long snapshot, long pixbuf, int x, int y, int width, int height);
+	protected native void native_drawBitmap(long snapshot, long pixbuf, int x, int y, int width, int height, int color);
 }

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

@@ -4,6 +4,7 @@ public class Paint {
 	public long skia_paint = 0;
 	private Typeface typeface = null;
 	public long skia_font = 0;
+	ColorFilter colorFilter = null;
 
 	public Paint() {
 		skia_paint = native_constructor();
@@ -64,6 +65,11 @@ public class Paint {
 	}
 	public float measureText(CharSequence text, int start, int end) { return 10; }
 
+	public ColorFilter setColorFilter(ColorFilter colorFilter) {
+		this.colorFilter = colorFilter;
+		return colorFilter;
+	}
+
 	public Shader setShader(Shader shader) { return shader; } 
 
 	public enum Style {

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

@@ -92,6 +92,10 @@ public class PorterDuff {
 		ADD(16),
 		OVERLAY(17);
 
-		Mode(int nativeInt) {}
+		public int nativeInt;
+
+		Mode(int nativeInt) {
+			this.nativeInt = nativeInt;
+		}
 	}
 }