[css-grid] Implementation of Baseline Self-Alignment

third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp

Index: third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
index 34394d9fefa93349d81016ebb644b680f17f947e..86b52918281aae069a2f47b0b87c5f53ffb537c2 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
@@ -2529,7 +2529,9 @@ int LayoutBlockFlow::lineCount(const RootInlineBox* stopRootInlineBox) const {
 }
 
 int LayoutBlockFlow::firstLineBoxBaseline() const {
-  if (isWritingModeRoot() && !isRubyRun())
+  // Orthogonal grid items can participante in baseline alignment along column
+  // axis.
+  if (isWritingModeRoot() && !isRubyRun() && !isGridItem())
     return -1;
   if (!childrenInline())
     return LayoutBlock::firstLineBoxBaseline();
@@ -2538,7 +2540,14 @@ int LayoutBlockFlow::firstLineBoxBaseline() const {
     DCHECK(fontData);
     if (!fontData)
       return -1;
-    return (firstLineBox()->logicalTop() +
+    // logicalTop() gives the distance to 'over-edge', 'top' for horizontal and
+    // 'right' for vertical-lr and vertical-rl. However, as it happens in
+    // inlineBlockBaseline we will flip lines to compute the baseline in case of
+    // vertical-lr mode, hence we want the distance to 'left' edge.
+    // We perform the same operatio in LayoutBlockFlow::inlineBlockBaseline.
+    return ((styleRef().isFlippedLinesWritingMode()
+                 ? logicalHeight() - firstLineBox()->logicalBottom()
+                 : firstLineBox()->logicalTop()) +
             fontData->getFontMetrics().ascent(firstRootBox()->baselineType()))
         .toInt();
   }