add support for custom Java Drawables

This is made possible, by adding a second Canvas implementation which
can be used to render directly to GdkSnapshot objects

For now the only implemented method is drawBitmap(), this is already
enough to make VectorDrawableCompat functional

src/api-impl/android/graphics/drawable/Drawable.java

@@ -28,7 +28,9 @@ public class Drawable {
 	private int[] mStateSet = new int[0];
 	public long paintable;
 
-	public Drawable() {}
+	public Drawable() {
+		this.paintable = native_constructor();
+	}
 
 	public Drawable(long paintable) {
 		this.paintable = paintable;
@@ -180,4 +182,5 @@ public class Drawable {
 	}
 
 	protected static native long native_paintable_from_path(String path);
+	protected native long native_constructor();
 }

src/api-impl/android/graphics/drawable/GradientDrawable.java

@@ -1,15 +1,7 @@
 package android.graphics.drawable;
 
-import android.graphics.Canvas;
-
 public class GradientDrawable extends Drawable {
 
-	@Override
-	public void draw(Canvas canvas) {
-		// TODO Auto-generated method stub
-		throw new UnsupportedOperationException("Unimplemented method 'draw'");
-	}
-
 	public void setColor(int color) {}
 
 	public void setCornerRadius(float cornerRadius) {}

src/api-impl/android/graphics/drawable/InsetDrawable.java

@@ -1,6 +1,5 @@
 package android.graphics.drawable;
 
-import android.graphics.Canvas;
 import android.graphics.Rect;
 
 public class InsetDrawable extends Drawable {
@@ -9,12 +8,6 @@ public class InsetDrawable extends Drawable {
 		super();
 	}
 
-	@Override
-	public void draw(Canvas canvas) {
-		// TODO Auto-generated method stub
-		throw new UnsupportedOperationException("Unimplemented method 'draw'");
-	}
-
 	public boolean getPadding(Rect padding) { return false; }
 	
 }

src/api-impl/android/graphics/drawable/RippleDrawable.java

@@ -1,15 +1,9 @@
 package android.graphics.drawable;
 
 import android.content.res.ColorStateList;
-import android.graphics.Canvas;
 
 public class RippleDrawable extends Drawable {
 
 	public RippleDrawable(ColorStateList colorStateList, Drawable drawable, Drawable drawable2) {}
 
-	@Override
-	public void draw(Canvas canvas) {
-		// TODO Auto-generated method stub
-		throw new UnsupportedOperationException("Unimplemented method 'draw'");
-	}
 }

src/api-impl/android/graphics/drawable/ShapeDrawable.java

@@ -1,6 +1,5 @@
 package android.graphics.drawable;
 
-import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.drawable.shapes.Shape;
 
@@ -9,11 +8,5 @@ public class ShapeDrawable extends Drawable {
 	public ShapeDrawable(Shape shape) {}
 
 	public Paint getPaint() {return new Paint();}
-
-	@Override
-	public void draw(Canvas canvas) {
-		// TODO Auto-generated method stub
-		throw new UnsupportedOperationException("Unimplemented method 'draw'");
-	}
 	
 }