[SVGDom] Add viewBox support

The main feature is <svg> viewBox and proper viewport support, but the CL
touches a few other things:

* refactor SkSVGRenderContext to auto-restore canvas state, and split the
  presentation bits into a separate CoW SkSVGPresentationContext

* introduce SkSVGNode::onPrepareToRender(), as a way for nodes to push their
  custom state before the actual onRender() call (instead of relying on
  non-virtual SkSVGNode to know about all possible state bits)

* add a "Type" suffix to SVG types, to disambiguate (e.g. SkSVGRectType vs.
  SkSVGRect)

R=robertphillips@google.com,stephana@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2222793002

Review-Url: https://codereview.chromium.org/2222793002

1 files changed, 8 insertions, 7 deletions

diff --git a/experimental/svg/model/SkSVGAttribute.h b/experimental/svg/model/SkSVGAttribute.h
index 64465b13c9..d05737b69f 100644
--- a/experimental/svg/model/SkSVGAttribute.h
+++ b/experimental/svg/model/SkSVGAttribute.h
@@ -11,12 +11,15 @@
 #include "SkSVGTypes.h"
 #include "SkTLazy.h"
 
+class SkSVGRenderContext;
+
 enum class SkSVGAttribute {
     kD,
     kFill,
     kHeight,
     kStroke,
     kTransform,
+    kViewBox,
     kWidth,
     kX,
     kY,
@@ -24,21 +27,19 @@ enum class SkSVGAttribute {
     kUnknown,
 };
 
-class SkSVGRenderContext;
-
 class SkSVGPresentationAttributes {
 public:
     SkSVGPresentationAttributes();
 
-    void setFill(const SkSVGColor&);
-    void setStroke(const SkSVGColor&);
+    void setFill(const SkSVGColorType&);
+    void setStroke(const SkSVGColorType&);
 
-    void applyTo(SkTCopyOnFirstWrite<SkSVGRenderContext>&) const;
+    void applyTo(SkSVGRenderContext*) const;
 
 private:
     // Color only for now.
-    SkSVGColor fFill;
-    SkSVGColor fStroke;
+    SkSVGColorType fFill;
+    SkSVGColorType fStroke;
 
     unsigned fFillIsSet   : 1;
     unsigned fStrokeIsSet : 1;