Update the snap points css properties

third_party/WebKit/Source/core/style/StyleScrollSnapData.h

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 #ifndef StyleScrollSnapData_h
 #define StyleScrollSnapData_h
 
-#include "core/style/ScrollSnapPoints.h"
+#include "core/style/ComputedStyleConstants.h"
 #include "platform/LengthPoint.h"
 #include "platform/wtf/Allocator.h"
 #include "platform/wtf/RefCounted.h"
 #include "platform/wtf/Vector.h"
 
 namespace blink {
 
+struct ScrollSnapType {
+  DISALLOW_NEW();
+
+  ScrollSnapType()
+      : axis(kSnapAxisNone), strictness(kSnapStrictnessProximity) {}

[majidvp, 2017/06/13 19:20:54]

snap type value grammar is "none | [ x | y | block | inline | both ] [ mandatory
| proximity ]?"

So actually axis does not have a "none" value but the snap type itself has one
and  defaults to it".

It seems we should just not have a is_none bool in the struct rather than
using a non standard axis value to indicate this.

[sunyunjia, 2017/06/14 18:36:21]

Done.

+
+  ScrollSnapType(const ScrollSnapType& other)
+      : axis(other.axis), strictness(other.strictness) {}
+
+  bool operator==(const ScrollSnapType& other) const {
+    return axis == other.axis && strictness == other.strictness;
+  }
+
+  bool operator!=(const ScrollSnapType& other) const {
+    return !(*this == other);
+  }
+
+  SnapAxis axis;
+  SnapStrictness strictness;
+};
+
+struct ScrollSnapAlign {
+  DISALLOW_NEW();
+
+  ScrollSnapAlign()
+      : alignmentX(kSnapAlignmentNone), alignmentY(kSnapAlignmentNone) {}
+
+  ScrollSnapAlign(const ScrollSnapAlign& other)
+      : alignmentX(other.alignmentX), alignmentY(other.alignmentY) {}
+
+  bool operator==(const ScrollSnapAlign& other) const {
+    return alignmentX == other.alignmentX && alignmentY == other.alignmentY;
+  }
+
+  bool operator!=(const ScrollSnapAlign& other) const {
+    return !(*this == other);
+  }
+
+  SnapAlignment alignmentX;
+  SnapAlignment alignmentY;
+};
+
+struct ScrollPadding {
+  DISALLOW_NEW();
+
+  ScrollPadding() : top(kFixed), right(kFixed), bottom(kFixed), left(kFixed) {}

[majidvp, 2017/06/13 19:20:53]

I don't think you should be initializing this to a "Fixed" size unit.

[sunyunjia, 2017/06/14 18:36:21]

Done.

+
+  explicit ScrollPadding(Length length)
+      : top(length), right(length), bottom(length), left(length) {}
+
+  ScrollPadding(const ScrollPadding& other)
+      : top(other.top),
+        right(other.right),
+        bottom(other.bottom),
+        left(other.left) {}
+
+  bool operator==(const ScrollPadding& other) const {
+    return top == other.top && right == other.right && bottom == other.bottom &&
+           left == other.left;
+  }
+
+  bool operator!=(const ScrollPadding& other) const {
+    return !(*this == other);
+  }
+
+  Length top;
+  Length right;
+  Length bottom;
+  Length left;
+};
+
+struct ScrollSnapMargin {

[majidvp, 2017/06/13 19:20:54]

I think you can factor out a common class for both ScrollPadding
and ScrollSnapMargin which is basically four lengths and typedef
these two. This may be usefull with other similiar properties.

Not sure what is a good name for it e.g., QuadLengthValue, MarginValue.

[sunyunjia, 2017/06/14 18:36:21]

Done.

+  DISALLOW_NEW();
+
+  ScrollSnapMargin()
+      : top(kFixed), right(kFixed), bottom(kFixed), left(kFixed) {}
+
+  explicit ScrollSnapMargin(Length length)
+      : top(length), right(length), bottom(length), left(length) {}
+
+  ScrollSnapMargin(const ScrollSnapMargin& other)
+      : top(other.top),
+        right(other.right),
+        bottom(other.bottom),
+        left(other.left) {}
+
+  bool operator==(const ScrollSnapMargin& other) const {
+    return top == other.top && right == other.right && bottom == other.bottom &&
+           left == other.left;
+  }
+
+  bool operator!=(const ScrollSnapMargin& other) const {
+    return !(*this == other);
+  }
+
+  Length top;
+  Length right;
+  Length bottom;
+  Length left;
+};
+
 class StyleScrollSnapData : public RefCounted<StyleScrollSnapData> {
  public:
   static PassRefPtr<StyleScrollSnapData> Create() {
     return AdoptRef(new StyleScrollSnapData);
   }
   PassRefPtr<StyleScrollSnapData> Copy() {
     return AdoptRef(new StyleScrollSnapData(*this));
   }
 
-  ScrollSnapPoints x_points_;
-  ScrollSnapPoints y_points_;
-  LengthPoint destination_;
-  Vector<LengthPoint> coordinates_;
+  ScrollSnapType type_;
+  ScrollSnapAlign align_;
+  ScrollPadding padding_;
+  ScrollSnapMargin margin_;
 
  private:
   StyleScrollSnapData();
-  StyleScrollSnapData(const StyleScrollSnapData&);
+  StyleScrollSnapData(const StyleScrollSnapData& other);
 };
 
 bool operator==(const StyleScrollSnapData&, const StyleScrollSnapData&);
 inline bool operator!=(const StyleScrollSnapData& a,
                        const StyleScrollSnapData& b) {
   return !(a == b);
 }
 
 }  // namespace blink
 
 #endif  // StyleScrollSnapData_h