Fix Style::operator== ignoring boxSizing (#2029)

`Style::operator==` compares every style field except `boxSizing_`, so two
styles that only differ in box sizing compare equal. `YGNodeCopyStyle` then
skips the copy and leaves the destination node with the old box sizing, and
callers that compare styles to decide whether a node needs relayout miss the
change.

Compare `boxSizing_` together with the other enum fields.

Author: kwy404

tests/YGStyleTest.cpp

@@ -51,6 +51,18 @@ TEST(YogaTest, copy_style_modified_same) {
   YGNodeFree(node1);
 }
 
+TEST(YogaTest, copy_style_box_sizing) {
+  YGNodeRef node0 = YGNodeNew();
+  YGNodeRef node1 = YGNodeNew();
+  YGNodeStyleSetBoxSizing(node1, YGBoxSizingContentBox);
+
+  YGNodeCopyStyle(node0, node1);
+  ASSERT_EQ(YGBoxSizingContentBox, YGNodeStyleGetBoxSizing(node0));
+
+  YGNodeFree(node0);
+  YGNodeFree(node1);
+}
+
 TEST(YogaTest, initialise_flexShrink_flexGrow) {
   YGNodeRef node0 = YGNodeNew();
   YGNodeStyleSetFlexShrink(node0, 1);

yoga/style/Style.h

@@ -653,6 +653,7 @@ class YG_EXPORT Style {
         alignItems_ == other.alignItems_ && alignSelf_ == other.alignSelf_ &&
         positionType_ == other.positionType_ && flexWrap_ == other.flexWrap_ &&
         overflow_ == other.overflow_ && display_ == other.display_ &&
+        boxSizing_ == other.boxSizing_ &&
         numbersEqual(flex_, pool_, other.flex_, other.pool_) &&
         numbersEqual(flexGrow_, pool_, other.flexGrow_, other.pool_) &&
         numbersEqual(flexShrink_, pool_, other.flexShrink_, other.pool_) &&