[LayoutNG] Initial support for the 'vertical-align' property

third_party/WebKit/Source/core/layout/ng/inline/ng_line_height_metrics.cc

Index: third_party/WebKit/Source/core/layout/ng/inline/ng_line_height_metrics.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/inline/ng_line_height_metrics.cc b/third_party/WebKit/Source/core/layout/ng/inline/ng_line_height_metrics.cc
index a3258a0c61e3c94f55dac3fdd1dbf66bc1e5f408..a6d4c437c2ff4c82837650852d628de83b03acbf 100644
--- a/third_party/WebKit/Source/core/layout/ng/inline/ng_line_height_metrics.cc
+++ b/third_party/WebKit/Source/core/layout/ng/inline/ng_line_height_metrics.cc
@@ -27,6 +27,7 @@ void NGLineHeightMetrics::Initialize(const FontMetrics& font_metrics,
 }
 
 void NGLineHeightMetrics::AddLeading(LayoutUnit line_height) {
+  DCHECK(!IsEmpty());
   LayoutUnit half_leading = (line_height - (ascent + descent)) / 2;
   // TODO(kojii): floor() is to make text dump compatible with legacy test
   // results. Revisit when we paint.
@@ -34,6 +35,12 @@ void NGLineHeightMetrics::AddLeading(LayoutUnit line_height) {
   descent = line_height - ascent;
 }
 
+void NGLineHeightMetrics::Move(LayoutUnit delta) {
+  DCHECK(!IsEmpty());
+  ascent -= delta;
+  descent += delta;
+}
+
 void NGLineHeightMetrics::Unite(const NGLineHeightMetrics& other) {
   ascent = std::max(ascent, other.ascent);
   descent = std::max(descent, other.descent);