[CSS Grid Layout] Fix positioned grid children position and size

Source/core/rendering/RenderBox.cpp

Index: Source/core/rendering/RenderBox.cpp
diff --git a/Source/core/rendering/RenderBox.cpp b/Source/core/rendering/RenderBox.cpp
index 7e63fe333b7890e7e5c48a84f0ad34a67eb493fb..a9836c79a1e1e0e6b0fc801d72ed7547e61b086e 100644
--- a/Source/core/rendering/RenderBox.cpp
+++ b/Source/core/rendering/RenderBox.cpp
@@ -2617,6 +2617,9 @@ LayoutUnit RenderBox::containingBlockLogicalWidthForPositioned(const RenderBoxMo
         }
     }
 
+    if (hasOverrideContainingBlockLogicalWidth())
+        return overrideContainingBlockContentLogicalWidth();
+
     if (containingBlock->isBox())
         return toRenderBox(containingBlock)->clientLogicalWidth();
 
@@ -2657,6 +2660,9 @@ LayoutUnit RenderBox::containingBlockLogicalHeightForPositioned(const RenderBoxM
         }
     }
 
+    if (hasOverrideContainingBlockLogicalHeight())
+        return overrideContainingBlockContentLogicalHeight();
+
     if (containingBlock->isBox()) {
         const RenderBlock* cb = containingBlock->isRenderBlock() ?
             toRenderBlock(containingBlock) : containingBlock->containingBlock();
@@ -2683,14 +2689,37 @@ LayoutUnit RenderBox::containingBlockLogicalHeightForPositioned(const RenderBoxM
     return heightResult;
 }
 
+static LayoutUnit computeInlineStaticPositionForGridChild(Length& logicalLeft, Length& logicalRight, const RenderBox* child, const RenderBoxModelObject* containerBlock, LayoutUnit containerLogicalWidth)
+{
+    ASSERT(containerBlock->isRenderGrid());
+    LayoutUnit staticPosition = 0;
+
+    if (containerBlock->style()->direction() == LTR) {
+        if (!logicalLeft.isAuto())
+            staticPosition += valueForLength(logicalLeft, containerLogicalWidth);
+        else if (!logicalRight.isAuto())
+            staticPosition -= valueForLength(logicalRight, containerLogicalWidth);
+    } else {
+        if (!logicalRight.isAuto())
+            staticPosition += valueForLength(logicalRight, containerLogicalWidth);
+        else if (!logicalLeft.isAuto())
+            staticPosition -= valueForLength(logicalLeft, containerLogicalWidth);
+    }
+    return staticPosition;
+}
+
 static void computeInlineStaticDistance(Length& logicalLeft, Length& logicalRight, const RenderBox* child, const RenderBoxModelObject* containerBlock, LayoutUnit containerLogicalWidth)
 {
-    if (!logicalLeft.isAuto() || !logicalRight.isAuto())
+    if ((!logicalLeft.isAuto() || !logicalRight.isAuto()) && (!containerBlock->isRenderGrid() || (containerBlock->isRenderGrid() && child->style()->gridColumnStart().isAuto())))
         return;
 
+    LayoutUnit staticPosition = 0;
+    if (containerBlock->isRenderGrid())
+        staticPosition = computeInlineStaticPositionForGridChild(logicalLeft, logicalRight, child, containerBlock, containerLogicalWidth);
+
     // FIXME: The static distance computation has not been patched for mixed writing modes yet.
     if (child->parent()->style()->direction() == LTR) {
-        LayoutUnit staticPosition = child->layer()->staticInlinePosition() - containerBlock->borderLogicalLeft();
+        staticPosition += child->layer()->staticInlinePosition() - containerBlock->borderLogicalLeft();
         for (RenderObject* curr = child->parent(); curr && curr != containerBlock; curr = curr->container()) {
             if (curr->isBox()) {
                 staticPosition += toRenderBox(curr)->logicalLeft();
@@ -2708,7 +2737,7 @@ static void computeInlineStaticDistance(Length& logicalLeft, Length& logicalRigh
         logicalLeft.setValue(Fixed, staticPosition);
     } else {
         RenderBox* enclosingBox = child->parent()->enclosingBox();
-        LayoutUnit staticPosition = child->layer()->staticInlinePosition() + containerLogicalWidth + containerBlock->borderLogicalLeft();
+        staticPosition += child->layer()->staticInlinePosition() + containerLogicalWidth + containerBlock->borderLogicalLeft();
         for (RenderObject* curr = child->parent(); curr; curr = curr->container()) {
             if (curr->isBox()) {
                 if (curr != containerBlock) {
@@ -3051,13 +3080,29 @@ void RenderBox::computePositionedLogicalWidthUsing(Length logicalWidth, const Re
     computeLogicalLeftPositionedOffset(computedValues.m_position, this, computedValues.m_extent, containerBlock, containerLogicalWidth);
 }
 
-static void computeBlockStaticDistance(Length& logicalTop, Length& logicalBottom, const RenderBox* child, const RenderBoxModelObject* containerBlock)
+static LayoutUnit computeBlockStaticPositionForGridItem(Length& logicalTop, Length& logicalBottom, const RenderBox* child, const RenderBoxModelObject* containerBlock, LayoutUnit containerLogicalHeight)
 {
-    if (!logicalTop.isAuto() || !logicalBottom.isAuto())
+    ASSERT(containerBlock->isRenderGrid());
+
+    LayoutUnit staticPosition = 0;
+    if (!logicalTop.isAuto())
+        staticPosition += valueForLength(logicalTop, containerLogicalHeight);
+    else if (!logicalBottom.isAuto())
+        staticPosition -= valueForLength(logicalBottom, containerLogicalHeight);
+    return staticPosition;
+}
+
+static void computeBlockStaticDistance(Length& logicalTop, Length& logicalBottom, const RenderBox* child, const RenderBoxModelObject* containerBlock, LayoutUnit containerLogicalHeight)
+{
+    if ((!logicalTop.isAuto() || !logicalBottom.isAuto()) && (!containerBlock->isRenderGrid() || (containerBlock->isRenderGrid() && child->style()->gridRowStart().isAuto())))
         return;
 
+    LayoutUnit staticLogicalTop = 0;
+    if (containerBlock->isRenderGrid())
+        staticLogicalTop = computeBlockStaticPositionForGridItem(logicalTop, logicalBottom, child, containerBlock, containerLogicalHeight);
+
     // FIXME: The static distance computation has not been patched for mixed writing modes.
-    LayoutUnit staticLogicalTop = child->layer()->staticBlockPosition() - containerBlock->borderBefore();
+    staticLogicalTop += child->layer()->staticBlockPosition() - containerBlock->borderBefore();
     for (RenderObject* curr = child->parent(); curr && curr != containerBlock; curr = curr->container()) {
         if (curr->isBox() && !curr->isTableRow())
             staticLogicalTop += toRenderBox(curr)->logicalTop();
@@ -3110,7 +3155,7 @@ void RenderBox::computePositionedLogicalHeight(LogicalExtentComputedValues& comp
 
     // see FIXME 1
     // Calculate the static distance if needed.
-    computeBlockStaticDistance(logicalTopLength, logicalBottomLength, this, containerBlock);
+    computeBlockStaticDistance(logicalTopLength, logicalBottomLength, this, containerBlock, containerLogicalHeight);
 
     // Calculate constraint equation values for 'height' case.
     LayoutUnit logicalHeight = computedValues.m_extent;
@@ -3516,7 +3561,7 @@ void RenderBox::computePositionedLogicalHeightReplaced(LogicalExtentComputedValu
      *    with the element's static position.
     \*-----------------------------------------------------------------------*/
     // see FIXME 1
-    computeBlockStaticDistance(logicalTop, logicalBottom, this, containerBlock);
+    computeBlockStaticDistance(logicalTop, logicalBottom, this, containerBlock, containerLogicalHeight);
 
     /*-----------------------------------------------------------------------*\
      * 3. If 'bottom' is 'auto', replace any 'auto' on 'margin-top' or