"Modularize" SkSG

* relocate all SkSG-related files under modules/sksg/
* fix various tidbits to make non-sksg builds possible
* drop obsolete SampleSGInval.cpp

Change-Id: I54e6c5bb1a09f45030fa8d607b3eb3f7cba78957
Reviewed-on: https://skia-review.googlesource.com/130025
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Klein <mtklein@google.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/modules/sksg/include/SkSGRenderNode.h b/modules/sksg/include/SkSGRenderNode.h
new file mode 100644
index 0000000000..4ca1aec616
--- /dev/null
+++ b/modules/sksg/include/SkSGRenderNode.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSGRenderNode_DEFINED
+#define SkSGRenderNode_DEFINED
+
+#include "SkSGNode.h"
+
+class SkCanvas;
+
+namespace sksg {
+
+/**
+ * Base class for nodes which can render to a canvas.
+ */
+class RenderNode : public Node {
+public:
+    // Render the node and its descendants to the canvas.
+    void render(SkCanvas*) const;
+
+protected:
+    RenderNode();
+
+    virtual void onRender(SkCanvas*) const = 0;
+
+private:
+    typedef Node INHERITED;
+};
+
+} // namespace sksg
+
+#endif // SkSGRenderNode_DEFINED