Reland "[svg] Relocate out of experimental"

Move the SVG rendering code to modules/svg, and componentize.
Also split into include/src/utils.

As external clients still reference the old header locations,
introduce temporary forwarding headers to facilitate the migration.

This reverts commit d6cf56fd3400f16aed443807390340c8efdcce1c.

TBR=

Change-Id: Ibadd7c8dc0464ec0c27841530ade0c2098305d20
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/327344
Commit-Queue: Florin Malita <fmalita@google.com>
Reviewed-by: Florin Malita <fmalita@google.com>
diff --git a/modules/svg/include/SkSVGPattern.h b/modules/svg/include/SkSVGPattern.h
new file mode 100644
index 0000000..64cebf4
--- /dev/null
+++ b/modules/svg/include/SkSVGPattern.h
@@ -0,0 +1,59 @@
+/*
+ * 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 SkSVGPattern_DEFINED
+#define SkSVGPattern_DEFINED
+
+#include "modules/svg/include/SkSVGHiddenContainer.h"
+#include "modules/svg/include/SkSVGTypes.h"
+
+class SkSVGRenderContext;
+
+class SkSVGPattern final : public SkSVGHiddenContainer {
+public:
+    ~SkSVGPattern() override = default;
+
+    static sk_sp<SkSVGPattern> Make() {
+        return sk_sp<SkSVGPattern>(new SkSVGPattern());
+    }
+
+    void setX(const SkSVGLength&);
+    void setY(const SkSVGLength&);
+    void setWidth(const SkSVGLength&);
+    void setHeight(const SkSVGLength&);
+    void setHref(const SkSVGStringType&);
+    void setPatternTransform(const SkSVGTransformType&);
+
+protected:
+    SkSVGPattern();
+
+    void onSetAttribute(SkSVGAttribute, const SkSVGValue&) override;
+
+    bool onAsPaint(const SkSVGRenderContext&, SkPaint*) const override;
+
+private:
+    struct PatternAttributes {
+        SkTLazy<SkSVGLength>        fX,
+                                    fY,
+                                    fWidth,
+                                    fHeight;
+        SkTLazy<SkSVGTransformType> fPatternTransform;
+    } fAttributes;
+
+    SkSVGStringType    fHref;
+
+    const SkSVGPattern* resolveHref(const SkSVGRenderContext&, PatternAttributes*) const;
+    const SkSVGPattern* hrefTarget(const SkSVGRenderContext&) const;
+
+    // TODO:
+    //   - patternUnits
+    //   - patternContentUnits
+
+    using INHERITED = SkSVGHiddenContainer;
+};
+
+#endif // SkSVGPattern_DEFINED