[SVGDom] Initial linear gradient support

Kind of a big change, to connect several new bits into something useful:

  * ID tracking & lookup
  * new asPaint() node virtual to support shader (and in the future filter) based paint servers
  * <defs>, <linearGradient> and <stop> element support
  * 'href', 'offset', 'stop-color', 'stop-opacity' attribute support
  * IRI/FuncIRI and rgb(...) parsing

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2327233003

Review-Url: https://codereview.chromium.org/2327233003

1 files changed, 44 insertions, 0 deletions

diff --git a/experimental/svg/model/SkSVGStop.h b/experimental/svg/model/SkSVGStop.h
new file mode 100644
index 0000000000..2ffbc5c852
--- /dev/null
+++ b/experimental/svg/model/SkSVGStop.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSVGStop_DEFINED
+#define SkSVGStop_DEFINED
+
+#include "SkSVGHiddenContainer.h"
+#include "SkSVGTypes.h"
+
+class SkSVGLengthContext;
+
+class SkSVGStop : public SkSVGHiddenContainer {
+public:
+    virtual ~SkSVGStop() = default;
+    static sk_sp<SkSVGStop> Make() {
+        return sk_sp<SkSVGStop>(new SkSVGStop());
+    }
+
+    const SkSVGLength& offset() const { return fOffset; }
+    const SkSVGColorType& stopColor() const { return fStopColor; }
+    const SkSVGNumberType& stopOpacity() const { return fStopOpacity; }
+
+    void setOffset(const SkSVGLength&);
+    void setStopColor(const SkSVGColorType&);
+    void setStopOpacity(const SkSVGNumberType&);
+
+protected:
+    void onSetAttribute(SkSVGAttribute, const SkSVGValue&) override;
+
+private:
+    SkSVGStop();
+
+    SkSVGLength          fOffset = SkSVGLength(0  , SkSVGLength::Unit::kPercentage);
+    SkSVGColorType    fStopColor = SkSVGColorType(SK_ColorBLACK);
+    SkSVGNumberType fStopOpacity = SkSVGNumberType(1);
+
+    typedef SkSVGHiddenContainer INHERITED;
+};
+
+#endif // SkSVGStop_DEFINED