Revert "Issue #1986 - Part 2: Add IsItemInlineAxisMainAxis() and rework some nsFrame code."

This reverts commit c3e18955ad.

layout/generic/nsFlexContainerFrame.cpp

@@ -1990,10 +1990,6 @@ FlexItem::FlexItem(ReflowInput& aFlexItemReflowInput,
              "placeholder frames should not be treated as flex items");
   MOZ_ASSERT(!(mFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW),
              "out-of-flow frames should not be treated as flex items");
-  MOZ_ASSERT(mIsInlineAxisMainAxis ==
-             nsFlexContainerFrame::IsItemInlineAxisMainAxis(mFrame),
-             "public API should be consistent with internal state (about "
-             "whether flex item's inline axis is flex container's main axis)");
 
   const ReflowInput* containerRS = aFlexItemReflowInput.mParentReflowInput;
   if (IsLegacyBox(containerRS->mFrame)) {
@@ -4425,41 +4421,6 @@ nsFlexContainerFrame::CalculatePackingSpace(uint32_t aNumThingsToPack,
   *aPackingSpaceRemaining -= totalEdgePackingSpace;
 }
 
-/* static */
-bool
-nsFlexContainerFrame::IsItemInlineAxisMainAxis(nsIFrame* aFrame)
-{
-  MOZ_ASSERT(aFrame && aFrame->IsFlexItem(), "expecting arg to be a flex item");
-  const WritingMode flexItemWM = aFrame->GetWritingMode();
-  const nsIFrame* flexContainer = aFrame->GetParent();
-
-  if (IsLegacyBox(flexContainer)) {
-    // For legacy boxes, the main axis is determined by "box-orient", and we can
-    // just directly check if that's vertical, and compare that to whether the
-    // item's WM is also vertical:
-    bool boxOrientIsVertical =
-      (flexContainer->StyleXUL()->mBoxOrient == StyleBoxOrient::Vertical);
-    return flexItemWM.IsVertical() == boxOrientIsVertical;
-  }
-
-  // For modern CSS flexbox, we get our return value by asking two questions
-  // and comparing their answers.
-  // Question 1: does aFrame have the same inline axis as its flex container?
-  bool itemInlineAxisIsParallelToParent =
-    !flexItemWM.IsOrthogonalTo(flexContainer->GetWritingMode());
-
-  // Question 2: is aFrame's flex container row-oriented? (This tells us
-  // whether the flex container's main axis is its inline axis.)
-  auto flexDirection = flexContainer->StylePosition()->mFlexDirection;
-  bool flexContainerIsRowOriented =
-    flexDirection == NS_STYLE_FLEX_DIRECTION_ROW ||
-    flexDirection == NS_STYLE_FLEX_DIRECTION_ROW_REVERSE;
-
-  // aFrame's inline axis is its flex container's main axis IFF the above
-  // questions have the same answer.
-  return flexContainerIsRowOriented == itemInlineAxisIsParallelToParent;
-}
-
 void
 nsFlexContainerFrame::DoFlexLayout(nsPresContext*           aPresContext,
                                    ReflowOutput&     aDesiredSize,

layout/generic/nsFlexContainerFrame.h

@@ -133,21 +133,6 @@ public:
                                     uint32_t* aNumPackingSpacesRemaining,
                                     nscoord* aPackingSpaceRemaining);
 
-  /**
-   * Given a frame for a flex item, this method returns true IFF that flex
-   * item's inline axis is the same as (i.e. not orthogonal to) its flex
-   * container's main axis.
-   *
-   * (This method is only intended to be used from external
-   * callers. Inside of flex reflow code, FlexItem::IsInlineAxisMainAxis() is
-   * equivalent & more optimal.)
-   *
-   * @param aFrame a flex item (must return true from IsFlexItem)
-   * @return true iff aFrame's inline axis is the same as (i.e. not orthogonal
-   *              to) its flex container's main axis. Otherwise, false.
-   */
-  static bool IsItemInlineAxisMainAxis(nsIFrame* aFrame);
-
 protected:
   // Protected constructor & destructor
   explicit nsFlexContainerFrame(nsStyleContext* aContext)

layout/generic/nsFrame.cpp

@@ -39,7 +39,6 @@
 #include "mozilla/Logging.h"
 #include "mozilla/Sprintf.h"
 #include "nsFrameManager.h"
-#include "nsFlexContainerFrame.h"
 #include "nsLayoutUtils.h"
 #include "LayoutLogging.h"
 #include "mozilla/RestyleManager.h"
@@ -4753,11 +4752,12 @@ nsFrame::ComputeSize(nsRenderingContext* aRenderingContext,
   }
   bool isFlexItem = (parentFrameType == nsGkAtoms::flexContainerFrame &&
                      !(GetStateBits() & NS_FRAME_OUT_OF_FLOW));
-
   bool isInlineFlexItem = false;
   if (isFlexItem) {
+    uint32_t flexDirection = GetParent()->StylePosition()->mFlexDirection;
     isInlineFlexItem =
-      nsFlexContainerFrame::IsItemInlineAxisMainAxis(this);
+      flexDirection == NS_STYLE_FLEX_DIRECTION_ROW ||
+      flexDirection == NS_STYLE_FLEX_DIRECTION_ROW_REVERSE;
 
     const nsStyleCoord* flexBasis = &(stylePos->mFlexBasis);
     SetCoordToFlexBasis(isInlineFlexItem, false, flexBasis,
@@ -4973,8 +4973,11 @@ nsFrame::ComputeSizeWithIntrinsicDimensions(nsRenderingContext*  aRenderingConte
   // from our style struct. (Otherwise, we'll be using an irrelevant value in
   // the aspect-ratio calculations below.)
   if (isFlexItem) {
+    uint32_t flexDirection =
+      GetParent()->StylePosition()->mFlexDirection;
     isInlineFlexItem =
-      nsFlexContainerFrame::IsItemInlineAxisMainAxis(this);
+      flexDirection == NS_STYLE_FLEX_DIRECTION_ROW ||
+      flexDirection == NS_STYLE_FLEX_DIRECTION_ROW_REVERSE;
 
     // If FlexItemMainSizeOverride frame-property is set, then that means the
     // flex container is imposing a main-size on this flex item for it to use