[svg] Implement feBlend filter

Note we are still not passing filters-blend-01-b because we don't yet
support feImage.

Bug: skia:10841
Change-Id: Ibca52c0e8e8d45e73473dea3b0252d6b81eaa584
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/354657
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Tyler Denniston <tdenniston@google.com>
diff --git a/modules/svg/include/SkSVGFeBlend.h b/modules/svg/include/SkSVGFeBlend.h
new file mode 100644
index 0000000..36d1f0f
--- /dev/null
+++ b/modules/svg/include/SkSVGFeBlend.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2020 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSVGFeBlend_DEFINED
+#define SkSVGFeBlend_DEFINED
+
+#include "modules/svg/include/SkSVGFe.h"
+#include "modules/svg/include/SkSVGTypes.h"
+
+class SkSVGFeBlend : public SkSVGFe {
+public:
+    enum class Mode {
+        kNormal,
+        kMultiply,
+        kScreen,
+        kDarken,
+        kLighten,
+    };
+
+    static sk_sp<SkSVGFeBlend> Make() { return sk_sp<SkSVGFeBlend>(new SkSVGFeBlend()); }
+
+    SVG_ATTR(Mode, Mode, Mode::kNormal)
+    SVG_ATTR(In2, SkSVGFeInputType, SkSVGFeInputType())
+
+protected:
+    sk_sp<SkImageFilter> onMakeImageFilter(const SkSVGRenderContext&,
+                                           const SkSVGFilterContext&) const override;
+
+    std::vector<SkSVGFeInputType> getInputs() const override {
+        return {this->getIn(), this->getIn2()};
+    }
+
+    bool parseAndSetAttribute(const char*, const char*) override;
+
+private:
+    SkSVGFeBlend() : INHERITED(SkSVGTag::kFeBlend) {}
+
+    using INHERITED = SkSVGFe;
+};
+
+#endif  // SkSVGFeBlend_DEFINED