CSS - Grid - intristic content with overflow:auto overlaps in grid

2026-09-05 23:38:38 +09:00 · 2017-08-17 20:46:41 +02:00 · 2017-08-17 20:46:41 +02:00 · b9bbb5d201
commit b9bbb5d201
parent 66276efa0a
18 changed files with 965 additions and 13 deletions
--- a/layout/generic/ReflowInput.cpp
+++ b/layout/generic/ReflowInput.cpp
@ -93,6 +93,9 @@ ReflowInput::ReflowInput(nsPresContext*       aPresContext,
  if (aFlags & B_CLAMP_MARGIN_BOX_MIN_SIZE) {
    mFlags.mBClampMarginBoxMinSize = true;
  }
+  if (aFlags & I_APPLY_AUTO_MIN_SIZE) {
+    mFlags.mApplyAutoMinSize = true;
+  }

  if (!(aFlags & CALLER_WILL_INIT)) {
    Init(aPresContext);
@ -242,6 +245,7 @@ ReflowInput::ReflowInput(
  mFlags.mIOffsetsNeedCSSAlign = mFlags.mBOffsetsNeedCSSAlign = false;
  mFlags.mIClampMarginBoxMinSize = !!(aFlags & I_CLAMP_MARGIN_BOX_MIN_SIZE);
  mFlags.mBClampMarginBoxMinSize = !!(aFlags & B_CLAMP_MARGIN_BOX_MIN_SIZE);
+  mFlags.mApplyAutoMinSize = !!(aFlags & I_APPLY_AUTO_MIN_SIZE);

  mDiscoveredClearance = nullptr;
  mPercentBSizeObserver = (aParentReflowInput.mPercentBSizeObserver &&
@ -1662,6 +1666,10 @@ ReflowInput::InitAbsoluteConstraints(nsPresContext* aPresContext,
    computeSizeFlags = ComputeSizeFlags(computeSizeFlags |
                         ComputeSizeFlags::eBClampMarginBoxMinSize);
  }
+  if (mFlags.mApplyAutoMinSize) {
+    computeSizeFlags = ComputeSizeFlags(computeSizeFlags |
+                         ComputeSizeFlags::eIApplyAutoMinSize);
+  }
  if (mFlags.mShrinkWrap) {
    computeSizeFlags =
      ComputeSizeFlags(computeSizeFlags | ComputeSizeFlags::eShrinkWrap);
@ -2375,6 +2383,10 @@ ReflowInput::InitConstraints(nsPresContext*     aPresContext,
        computeSizeFlags = ComputeSizeFlags(computeSizeFlags |
                             ComputeSizeFlags::eBClampMarginBoxMinSize);
      }
+      if (mFlags.mApplyAutoMinSize) {
+        computeSizeFlags = ComputeSizeFlags(computeSizeFlags |
+                             ComputeSizeFlags::eIApplyAutoMinSize);
+      }
      if (mFlags.mShrinkWrap) {
        computeSizeFlags =
          ComputeSizeFlags(computeSizeFlags | ComputeSizeFlags::eShrinkWrap);
--- a/layout/generic/ReflowInput.h
+++ b/layout/generic/ReflowInput.h
@ -220,6 +220,7 @@ public:
    uint32_t mStaticPosIsCBOrigin:1; // the STATIC_POS_IS_CB_ORIGIN ctor flag
    uint32_t mIClampMarginBoxMinSize:1; // the I_CLAMP_MARGIN_BOX_MIN_SIZE ctor flag
    uint32_t mBClampMarginBoxMinSize:1; // the B_CLAMP_MARGIN_BOX_MIN_SIZE ctor flag
+    uint32_t mApplyAutoMinSize : 1;       // the I_APPLY_AUTO_MIN_SIZE ctor flag

    // If set, the following two flags indicate that:
    // (1) this frame is absolutely-positioned (or fixed-positioned).
@ -738,6 +739,9 @@ public:

    // Pass ComputeSizeFlags::eBClampMarginBoxMinSize to ComputeSize().
    B_CLAMP_MARGIN_BOX_MIN_SIZE = (1<<6),
+
+    // Pass ComputeSizeFlags::eIApplyAutoMinSize to ComputeSize().
+    I_APPLY_AUTO_MIN_SIZE = (1<<7),
  };

  // This method initializes various data members. It is automatically
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@ -4781,7 +4781,7 @@ nsFrame::ComputeSize(nsRenderingContext* aRenderingContext,
      ComputeISizeValue(aRenderingContext, aCBSize.ISize(aWM),
                        boxSizingAdjust.ISize(aWM), boxSizingToMarginEdgeISize,
                        minISizeCoord, aFlags);
-  } else if (MOZ_UNLIKELY(isGridItem)) {
+  } else if (MOZ_UNLIKELY(aFlags & eIApplyAutoMinSize)) {
    // This implements "Implied Minimum Size of Grid Items".
    // https://drafts.csswg.org/css-grid/#min-size-auto
    minISize = std::min(maxISize, GetMinISize(aRenderingContext));
--- a/layout/generic/nsGridContainerFrame.cpp
+++ b/layout/generic/nsGridContainerFrame.cpp
@ -818,8 +818,11 @@ struct nsGridContainerFrame::GridItemInfo
    // Ditto *-content:[last ]baseline. Mutually exclusive w. eSelfBaseline.
    eContentBaseline =       0x10,
    eAllBaselineBits = eIsBaselineAligned | eSelfBaseline | eContentBaseline,
+    // Should apply Automatic Minimum Size per:
+    // https://drafts.csswg.org/css-grid/#min-size-auto
+    eApplyAutoMinSize =      0x20,
    // Clamp per https://drafts.csswg.org/css-grid/#min-size-auto
-    eClampMarginBoxMinSize = 0x20,
+    eClampMarginBoxMinSize = 0x40,
  };

  explicit GridItemInfo(nsIFrame* aFrame,
@ -851,11 +854,11 @@ struct nsGridContainerFrame::GridItemInfo
    return aAlign;
  }

-  // Return true if we should we clamp this item's Automatic Minimum Size.
+  // Return true if we should apply Automatic Minimum Size to this item.
  // https://drafts.csswg.org/css-grid/#min-size-auto
-  bool ShouldClampMinSize(WritingMode aContainerWM,
-                          LogicalAxis aContainerAxis,
-                          nscoord aPercentageBasis) const
+  bool ShouldApplyAutoMinSize(WritingMode aContainerWM,
+                              LogicalAxis aContainerAxis,
+                              nscoord aPercentageBasis) const
  {
    const auto pos = mFrame->StylePosition();
    const auto& size = aContainerAxis == eLogicalAxisInline ?
@ -3977,9 +3980,9 @@ nsGridContainerFrame::Tracks::ResolveIntrinsicSizeStep1(
  WritingMode wm = aState.mWM;
  // Calculate data for "Automatic Minimum Size" clamping, if needed.
  bool needed = ((sz.mState & TrackSize::eIntrinsicMinSizing) ||
-                 aConstraint == SizingConstraint::eNoConstraint);
-  if (needed && TrackSize::IsDefiniteMaxSizing(sz.mState) &&
-      aGridItem.ShouldClampMinSize(wm, mAxis, aPercentageBasis)) {
+                 aConstraint == SizingConstraint::eNoConstraint) &&
+                (aGridItem.mState[mAxis] & ItemState::eApplyAutoMinSize);
+  if (needed && TrackSize::IsDefiniteMaxSizing(sz.mState)) {
    if (sz.mState & TrackSize::eIntrinsicMinSizing) {
      auto maxCoord = aFunctions.MaxSizingFor(aRange.mStart);
      cache.mMinSizeClamp =
@ -4382,6 +4385,14 @@ nsGridContainerFrame::Tracks::ResolveIntrinsicSize(
  iter.Reset();
  for (; !iter.AtEnd(); iter.Next()) {
    auto& gridItem = aGridItems[iter.GridItemIndex()];
+
+    // Check if we need to apply "Automatic Minimum Size" and cache it.
+    MOZ_ASSERT(!(gridItem.mState[mAxis] & ItemState::eApplyAutoMinSize),
+               "Why is eApplyAutoMinSize set already?");
+    if (gridItem.ShouldApplyAutoMinSize(wm, mAxis, aPercentageBasis)) {
+      gridItem.mState[mAxis] |= ItemState::eApplyAutoMinSize;
+    }
+
    const GridArea& area = gridItem.mArea;
    const LineRange& lineRange = area.*aRange;
    uint32_t span = lineRange.Extent();
@ -4407,9 +4418,9 @@ nsGridContainerFrame::Tracks::ResolveIntrinsicSize(
        CachedIntrinsicSizes cache;
        // Calculate data for "Automatic Minimum Size" clamping, if needed.
        bool needed = ((state & TrackSize::eIntrinsicMinSizing) ||
-                       aConstraint == SizingConstraint::eNoConstraint);
-        if (needed && TrackSize::IsDefiniteMaxSizing(state) &&
-            gridItem.ShouldClampMinSize(wm, mAxis, aPercentageBasis)) {
+                       aConstraint == SizingConstraint::eNoConstraint) &&
+                      (gridItem.mState[mAxis] & ItemState::eApplyAutoMinSize);
+        if (needed && TrackSize::IsDefiniteMaxSizing(state)) {
          nscoord minSizeClamp = 0;
          for (auto i = lineRange.mStart, end = lineRange.mEnd; i < end; ++i) {
            auto maxCoord = aFunctions.MaxSizingFor(i);
@ -4445,11 +4456,14 @@ nsGridContainerFrame::Tracks::ResolveIntrinsicSize(
          gridItem.mState[mAxis] |= ItemState::eIsFlexing;
        } else if (aConstraint == SizingConstraint::eNoConstraint &&
                   TrackSize::IsDefiniteMaxSizing(state) &&
-                   gridItem.ShouldClampMinSize(wm, mAxis, aPercentageBasis)) {
+                   (gridItem.mState[mAxis] & ItemState::eApplyAutoMinSize)) {
          gridItem.mState[mAxis] |= ItemState::eClampMarginBoxMinSize;
        }
      }
    }
+    MOZ_ASSERT(!(gridItem.mState[mAxis] & ItemState::eClampMarginBoxMinSize) ||
+               (gridItem.mState[mAxis] & ItemState::eApplyAutoMinSize),
+               "clamping only applies to Automatic Minimum Size");
  }

  // Step 2.
@ -5231,6 +5245,9 @@ nsGridContainerFrame::ReflowInFlowChild(nsIFrame*              aChild,
    } else {
      aChild->Properties().Delete(BClampMarginBoxMinSizeProperty());
    }
+    if ((aGridItemInfo->mState[childIAxis] & ItemState::eApplyAutoMinSize)) {
+      flags |= ReflowInput::I_APPLY_AUTO_MIN_SIZE;
+    }
  }

  if (!isConstrainedBSize) {
--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@ -2105,6 +2105,14 @@ public:
     */
    eIClampMarginBoxMinSize = 1 << 2, // clamp in our inline axis
    eBClampMarginBoxMinSize = 1 << 3, // clamp in our block axis
+    /**
+     * The frame is stretching (per CSS Box Alignment) and doesn't have an
+     * Automatic Minimum Size in the indicated axis.
+     * (may be used for both flex/grid items, but currently only used for Grid)
+     * https://drafts.csswg.org/css-grid/#min-size-auto
+     * https://drafts.csswg.org/css-align-3/#valdef-justify-self-stretch
+     */
+    eIApplyAutoMinSize = 1 << 4, // only has an effect when eShrinkWrap is false
  };

  /**
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-001-ref.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-001-ref.html
@ -0,0 +1,78 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Reference: stretching overflow!=visible items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px 30px 3px / 7px 80px 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+  min-width:0;
+  min-height:0;
+  box-sizing: border-box;
+}
+
+.oa, .os, .oh { width:80px; height:30px; }
+.m.oa, .m.os, .m.oh { width:70px; height:24px; }
+.oa { overflow: auto; }
+.os { overflow: scroll; }
+.oh { overflow: hidden; }
+.m  { margin: 1px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  " style="width:112px"><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   " style="width:112px"><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  " style="height:112px"><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   " style="height:112px"><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-001.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-001.html
@ -0,0 +1,74 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Test: stretching overflow!=visible items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <link rel="match" href="grid-item-overflow-stretch-001-ref.html">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px auto 3px / 7px auto 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+}
+
+.oa { overflow: auto; }
+.os { overflow: scroll; }
+.oh { overflow: hidden; }
+.m  { margin: 1px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   "><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   "><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-002-ref.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-002-ref.html
@ -0,0 +1,79 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Reference: stretching overflow!=visible vertical-rl items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px 30px 3px / 7px 80px 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+  writing-mode: vertical-rl;
+  min-width:0;
+  min-height:0;
+  box-sizing: border-box;
+}
+
+.oa, .os, .oh { width:80px; height:30px; }
+.m.oa, .m.os, .m.oh { width:70px; height:24px; }
+.oa { overflow: auto; }
+.os { overflow: scroll; }
+.oh { overflow: hidden; }
+.m  { margin: 1px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  " style="width:112px"><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   " style="width:112px"><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  " style="height:112px"><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   " style="height:112px"><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-002.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-002.html
@ -0,0 +1,75 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Test: stretching overflow!=visible vertical-rl items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <link rel="match" href="grid-item-overflow-stretch-002-ref.html">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px auto 3px / 7px auto 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+  writing-mode: vertical-rl;
+}
+
+.oa { overflow: auto; }
+.os { overflow: scroll; }
+.oh { overflow: hidden; }
+.m  { margin: 1px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   "><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   "><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-003-ref.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-003-ref.html
@ -0,0 +1,84 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Reference: margin:auto stretch items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px 30px 3px / 7px 112px 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+.c2 { grid-template-columns: 7px 122px 3px; }
+.h > .grid { grid: 7px 112px 3px / 7px 80px 3px; }
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+  margin: 0 auto;
+  justify-self:start;
+  align-self:start;
+  height:28px;
+}
+.c2 > * { height:22px; }
+.h .grid > * {
+  margin: 10px 0 0 10px;
+  justify-self:center;
+  align-self:center;
+  width:5px;
+  height:110px;
+}
+
+.m  { margin: 1px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid c2"><span class="m oa"><x></x></span></div>
+<div class="grid c2"><span class="m os"><x></x></span></div>
+<div class="grid c2"><span class="m oh"><x></x></span></div>
+<div class="grid c2"><span class="m   "><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   "><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-003.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-003.html
@ -0,0 +1,75 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Test: margin:auto stretch items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <link rel="match" href="grid-item-overflow-stretch-003-ref.html">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px auto 3px / 7px auto 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+  margin: 0 auto;
+}
+.h .grid > * {
+  margin: auto;
+}
+
+.m  { margin: 1px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   "><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="oa"><x></x></span></div>
+<div class="grid"><span class="os"><x></x></span></div>
+<div class="grid"><span class="oh"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m oa"><x></x></span></div>
+<div class="grid"><span class="m os"><x></x></span></div>
+<div class="grid"><span class="m oh"><x></x></span></div>
+<div class="grid"><span class="m   "><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-004-ref.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-004-ref.html
@ -0,0 +1,88 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Reference: stretching items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 90px;
+  height: 50px;
+  grid: 7px 30px 3px / 7px 102px 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+.c2 { grid: 7px 30x 3px / 7px 112px 3px; grid-gap: 5px;}
+.c3 { grid: 7px 30x 3px / 7px 70px 3px; grid-gap: 5px;}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+  min-width: 0;
+  max-width: 100px;
+}
+.h .grid > * {
+  min-height: 0;
+  max-height: 100px;
+  justify-self:center safe;
+  align-self:center safe;
+}
+.h > .grid { grid: 7px 102px 3px / 7px 70px 3px; grid-gap: 5px;}
+.h > .grid.c2 { grid: 7px 30px 3px / 7px 70px 3px; grid-gap: 5px;}
+.h > .grid.c3 { grid: 7px 108px 3px / 7px 70px 3px; grid-gap: 5px;}
+
+.oa { overflow: auto; }
+.p { width: 100%; }
+.h .grid > .p { height: 100%; }
+.x { width:5px; }
+.h .grid > .x { max-height:5px; }
+.m { margin: 1px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class="p oa"><x></x></span></div>
+<div class="grid"><span class="p "><x></x></span></div>
+<div class="grid c2"><span class="p x" style="height:5px; margin-left:31.5px; margin-top:11.5px"><x></x></span></div>
+<div class="grid c2"><span class="  " style="width:68px"><x></x></span></div>
+
+<br>
+
+<div class="grid c3"><span class="p m oa"><x></x></span></div>
+<div class="grid c3"><span class="p m"><x></x></span></div>
+<div class="grid c2"><span class="m p x"><x></x></span></div>
+<div class="grid c2"><span class="m " style="width:58px"><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="p oa"><x></x></span></div>
+<div class="grid"><span class="p "><x></x></span></div>
+<div class="grid c2"><span class="p x" style=""><x></x></span></div>
+<div class="grid c2"><span class="  " style="height:28px; width:68px;"><x></x></span></div>
+
+<br>
+
+<div class="grid c3"><span class="m p oa"><x></x></span></div>
+<div class="grid c3"><span class="m p"><x></x></span></div>
+<div class="grid c2"><span class="m p x" style="justify-self:start;align-self:start"><x></x></span></div>
+<div class="grid c2"><span class="m  " style="height:22px; width:58px"><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-004.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-004.html
@ -0,0 +1,82 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Test: stretching items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <link rel="match" href="grid-item-overflow-stretch-004-ref.html">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 90px;
+  height: 50px;
+  grid: 7px auto 3px / 7px auto 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+  min-width: 0;
+  max-width: 100px;
+}
+.h .grid > * {
+  min-height: 0;
+  max-height: 100px;
+}
+
+.oa { overflow: auto; }
+.p { width: 100%; }
+.h .grid > .p { height: 100%; }
+.x { max-width:5px; margin:auto; }
+.h .grid > .x { max-height:5px; }
+.m { margin: 1px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class="p oa"><x></x></span></div>
+<div class="grid"><span class="p "><x></x></span></div>
+<div class="grid"><span class="p x"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="p m oa"><x></x></span></div>
+<div class="grid"><span class="p m"><x></x></span></div>
+<div class="grid"><span class="m p x"><x></x></span></div>
+<div class="grid"><span class="m "><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="p oa"><x></x></span></div>
+<div class="grid"><span class="p "><x></x></span></div>
+<div class="grid"><span class="p x"><x></x></span></div>
+<div class="grid"><span class="  "><x></x></span></div>
+
+<br>
+
+<div class="grid"><span class="m p oa"><x></x></span></div>
+<div class="grid"><span class="m p"><x></x></span></div>
+<div class="grid"><span class="m p x"><x></x></span></div>
+<div class="grid"><span class="m  "><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-005-ref.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-005-ref.html
@ -0,0 +1,83 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Reference: stretching overflow!=visible items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px auto 3px / 7px auto 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+     -moz-appearance: none;
+  -webkit-appearance: none;
+          appearance: none;
+  min-width:0;
+  min-height:0;
+  box-sizing: border-box;
+}
+
+.oa, .os, .oh { width:80px; height:30px; }
+.m.oa, .m.os, .m.oh { width:70px; height:8px; }
+.oa { overflow: auto; }
+.os { overflow: scroll; }
+.oh { overflow: hidden; }
+.ov { justify-self: start; }
+.m.ov { align-self: start; }
+.m  { margin: 17px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><input class="oa"></div>
+<div class="grid"><input class="os"></div>
+<div class="grid"><input class="oh"></div>
+<div class="grid"><input class="ov"></div>
+
+<br>
+
+<div class="grid"><input class="m oa"></div>
+<div class="grid"><input class="m os"></div>
+<div class="grid"><input class="m oh"></div>
+<div class="grid"><input class="m ov"></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><input class="oa"></div>
+<div class="grid"><input class="os"></div>
+<div class="grid"><input class="oh"></div>
+<div class="grid"><input class="ov"></div>
+
+<br>
+
+<div class="grid"><input class="m oa"></div>
+<div class="grid"><input class="m os"></div>
+<div class="grid"><input class="m oh"></div>
+<div class="grid"><input class="m ov"></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-005.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-005.html
@ -0,0 +1,77 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Test: stretching overflow!=visible items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <link rel="match" href="grid-item-overflow-stretch-005-ref.html">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px auto 3px / 7px auto 3px;
+  grid-gap: 5px;
+  border:1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border:1px solid;
+     -moz-appearance: none;
+  -webkit-appearance: none;
+          appearance: none;
+}
+
+.oa { overflow: auto; }
+.os { overflow: scroll; }
+.oh { overflow: hidden; }
+.m  { margin: 17px 3px 5px 7px; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><input class="oa"></div>
+<div class="grid"><input class="os"></div>
+<div class="grid"><input class="oh"></div>
+<div class="grid"><input class="  "></div>
+
+<br>
+
+<div class="grid"><input class="m oa"></div>
+<div class="grid"><input class="m os"></div>
+<div class="grid"><input class="m oh"></div>
+<div class="grid"><input class="m   "></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><input class="oa"></div>
+<div class="grid"><input class="os"></div>
+<div class="grid"><input class="oh"></div>
+<div class="grid"><input class="  "></div>
+
+<br>
+
+<div class="grid"><input class="m oa"></div>
+<div class="grid"><input class="m os"></div>
+<div class="grid"><input class="m oh"></div>
+<div class="grid"><input class="m   "></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-006-ref.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-006-ref.html
@ -0,0 +1,54 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Reference: stretching overflow visible items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-flex;
+  width: 90px;
+  height: 40px;
+  padding: 7px 3px 3px 7px;
+  border: 1px solid;
+}
+
+.grid > * {
+  border: 1px solid;
+  margin: 5px;
+}
+
+.m  { margin: 6px 8px 10px 12px; }
+.ma { margin: auto; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class=""><x></x></span></div>
+<div class="grid"><span class="m"><x></x></span></div>
+<div class="grid"><span class="ma" style="margin-left:5px"><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class="" style="flex:1"><x></x></span></div>
+<div class="grid"><span class="m" style="flex:1"><x></x></span></div>
+<div class="grid"><span class="ma" style="margin-top:5px"><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/grid-item-overflow-stretch-006.html
+++ b/layout/reftests/css-grid/grid-item-overflow-stretch-006.html
@ -0,0 +1,56 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Grid Test: stretching overflow visible items</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1348857">
+  <link rel="match" href="grid-item-overflow-stretch-006-ref.html">
+  <style type="text/css">
+body,html { color:black; background:white; font:16px/1 monospace; padding:0; margin:0; }
+
+.grid {
+  display: inline-grid;
+  width: 100px;
+  height: 50px;
+  grid: 7px minmax(20px, auto) 3px / 7px minmax(20px, auto) 3px;
+  grid-gap: 5px;
+  border: 1px solid;
+}
+
+.grid > * {
+  grid-area: 2/2;
+  border: 1px solid;
+}
+
+.m  { margin: 1px 3px 5px 7px; }
+.ma { margin: auto; }
+
+x { display:block; width:110px; height:5px; background:grey; }
+.h .grid x { width:5px; height:110px; }
+
+br { clear:both; }
+  </style>
+</head>
+<body>
+
+<div class="grid"><span class=""><x></x></span></div>
+<div class="grid"><span class="m"><x></x></span></div>
+<div class="grid"><span class="ma"><x></x></span></div>
+
+<br>
+
+<div class="h">
+
+<div class="grid"><span class=""><x></x></span></div>
+<div class="grid"><span class="m"><x></x></span></div>
+<div class="grid"><span class="ma"><x></x></span></div>
+
+<br>
+
+</div>
+
+</body>
+</html>
--- a/layout/reftests/css-grid/reftest.list
+++ b/layout/reftests/css-grid/reftest.list
@ -116,6 +116,12 @@ skip-if(Android) == grid-auto-min-sizing-percent-001.html grid-auto-min-sizing-p
 == grid-item-auto-min-size-clamp-005.html grid-item-auto-min-size-clamp-005-ref.html
 == grid-item-auto-min-size-clamp-006.html grid-item-auto-min-size-clamp-006-ref.html
 == grid-item-auto-min-size-clamp-007.html grid-item-auto-min-size-clamp-007-ref.html
+== grid-item-overflow-stretch-001.html grid-item-overflow-stretch-001-ref.html
+== grid-item-overflow-stretch-002.html grid-item-overflow-stretch-002-ref.html
+== grid-item-overflow-stretch-003.html grid-item-overflow-stretch-003-ref.html
+== grid-item-overflow-stretch-004.html grid-item-overflow-stretch-004-ref.html
+== grid-item-overflow-stretch-005.html grid-item-overflow-stretch-005-ref.html
+== grid-item-overflow-stretch-006.html grid-item-overflow-stretch-006-ref.html
 == grid-item-canvas-001.html grid-item-canvas-001-ref.html
 skip-if(Android) == grid-item-button-001.html grid-item-button-001-ref.html
 == grid-item-table-stretch-001.html grid-item-table-stretch-001-ref.html