Make sp- via support SkDrawables; add a GM to test it.

gm/drawable.cpp

Index: gm/drawable.cpp
diff --git a/gm/drawable.cpp b/gm/drawable.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..375ce73cbe6dc6fe9ca98fa377067c41b6fdbec0
--- /dev/null
+++ b/gm/drawable.cpp
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkCanvas.h"
+#include "SkDrawable.h"
+
+struct MyDrawable : public SkDrawable {
+    SkRect onGetBounds() override {
+        return SkRect::MakeWH(640, 480);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+       SkPath path;
+       path.moveTo(10, 10);
+       path.conicTo(10, 90, 50, 90, 0.9f);
+
+       SkPaint paint;
+       paint.setColor(SK_ColorBLUE);
+       canvas->drawRect(path.getBounds(), paint);
+
+       paint.setAntiAlias(true);
+       paint.setColor(SK_ColorWHITE);
+       canvas->drawPath(path, paint);
+    }
+};
+
+DEF_SIMPLE_GM(Drawables, canvas, 640, 480) {
+    SkAutoTUnref<SkDrawable> d(new MyDrawable);
+    canvas->drawDrawable(d);
+}