[LayoutNG] Use NGLogical[Offset|Size] for NGFragment

third_party/WebKit/Source/core/layout/ng/geometry/ng_physical_offset.cc

Index: third_party/WebKit/Source/core/layout/ng/geometry/ng_physical_offset.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/geometry/ng_physical_offset.cc b/third_party/WebKit/Source/core/layout/ng/geometry/ng_physical_offset.cc
index 79c94e7b87670cb5fab76588afdbbd2d9f28f63f..9ede836b6e6ab39414f360c30193b5e8f4308def 100644
--- a/third_party/WebKit/Source/core/layout/ng/geometry/ng_physical_offset.cc
+++ b/third_party/WebKit/Source/core/layout/ng/geometry/ng_physical_offset.cc
@@ -4,10 +4,16 @@
 
 #include "core/layout/ng/geometry/ng_physical_offset.h"
 
+#include "core/layout/ng/geometry/ng_logical_offset.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
+NGLogicalOffset NGPhysicalOffset::ConvertToLogical(NGWritingMode mode) const {
+  return mode == kHorizontalTopBottom ? NGLogicalOffset(left, top)
+                                      : NGLogicalOffset(top, left);

[cbiesinger, 2017/04/10 20:55:51]

Is that correct? For vertical-rl, I am not sure that left is the inline offset,
shouldn't it be width-left?

[atotic, 2017/04/10 22:44:35]

I agree. 

Computing physical offset of fragment from logical might be even more
complicated.

In algorithms:
for physical position, you want offset of top/left corner.
for logical position, you want offset of inline-start/block-start corner.

These corners are not the same in vertical modes. inline-start/block-start is
right/bottom corner in vertical-rl.

To compute these, you need two sizes, parent and fragment.

There should be methods on NGPhysicalFragment that also expose PhysicalSize and
PhysicalOffset.

+}
+
 NGPhysicalOffset NGPhysicalOffset::operator+(
     const NGPhysicalOffset& other) const {
   return NGPhysicalOffset{this->left + other.left, this->top + other.top};