[css-grid] Implementation of Baseline Self-Alignment

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 2511 matching lines @@
   for (const RootInlineBox* box = firstRootBox(); box;
        box = box->nextRootBox()) {
     count++;
     if (box == stopRootInlineBox)
       break;
   }
   return count;
 }
 
 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();
   if (firstLineBox()) {
     const SimpleFontData* fontData = style(true)->font().primaryFont();
     DCHECK(fontData);
     if (!fontData)
       return -1;
+    // fontMetrics 'ascent' is the distance above the baseline to the 'over'
+    // edge, which is 'top' for horizontal and 'right' for vertical-lr and
+    // vertical-rl. However, firstLineBox()->logicalTop() gives the offset from
+    // the 'left' edge for vertical-lr, hence we need to use the Font Metrics
+    // 'descent' instead. The result should be handled accordingly by the caller
+    // as a 'descent' value, in order to compute properly the max baseline.
+    if (styleRef().isFlippedLinesWritingMode()) {
+      return (firstLineBox()->logicalTop() +
+              fontData->getFontMetrics().descent(
+                  firstRootBox()->baselineType()))
+          .toInt();
+    }
     return (firstLineBox()->logicalTop() +
             fontData->getFontMetrics().ascent(firstRootBox()->baselineType()))
         .toInt();
   }
   return -1;
 }
 
 int LayoutBlockFlow::inlineBlockBaseline(
     LineDirectionMode lineDirection) const {
   // CSS2.1 states that the baseline of an 'inline-block' is:
@@ skipping 2051 matching lines @@
   return LayoutBlock::invalidatePaintIfNeeded(paintInvalidationState);
 }
 
 void LayoutBlockFlow::invalidateDisplayItemClients(
     PaintInvalidationReason invalidationReason) const {
   BlockFlowPaintInvalidator(*this).invalidateDisplayItemClients(
       invalidationReason);
 }
 
 }  // namespace blink