--- a/layout/generic/nsFloatManager.cpp
+++ b/layout/generic/nsFloatManager.cpp
@@ -256,21 +256,18 @@ nsFloatManager::GetFlowArea(WritingMode 
 nsresult
 nsFloatManager::AddFloat(nsIFrame* aFloatFrame, const LogicalRect& aMarginRect,
                          WritingMode aWM, const nsSize& aContainerSize)
 {
   CHECK_BLOCK_DIR(aWM);
   NS_ASSERTION(aMarginRect.ISize(aWM) >= 0, "negative inline size!");
   NS_ASSERTION(aMarginRect.BSize(aWM) >= 0, "negative block size!");
 
-  FloatInfo info(aFloatFrame,
-                 aMarginRect.LineLeft(aWM, aContainerSize) + mLineLeft,
-                 aMarginRect.BStart(aWM) + mBlockStart,
-                 aMarginRect.ISize(aWM),
-                 aMarginRect.BSize(aWM));
+  FloatInfo info(aFloatFrame, mLineLeft, mBlockStart, aMarginRect, aWM,
+                 aContainerSize);
 
   // Set mLeftBEnd and mRightBEnd.
   if (HasAnyFloats()) {
     FloatInfo &tail = mFloats[mFloats.Length() - 1];
     info.mLeftBEnd = tail.mLeftBEnd;
     info.mRightBEnd = tail.mRightBEnd;
   } else {
     info.mLeftBEnd = nscoord_MIN;
@@ -524,20 +521,25 @@ nsFloatManager::ClearContinues(StyleClea
           (aBreakType == StyleClear::Both ||
            aBreakType == StyleClear::Right));
 }
 
 /////////////////////////////////////////////////////////////////////////////
 // FloatInfo
 
 nsFloatManager::FloatInfo::FloatInfo(nsIFrame* aFrame,
-                                     nscoord aLineLeft, nscoord aBStart,
-                                     nscoord aISize, nscoord aBSize)
+                                     nscoord aLineLeft, nscoord aBlockStart,
+                                     const LogicalRect& aMarginRect,
+                                     WritingMode aWM,
+                                     const nsSize& aContainerSize)
   : mFrame(aFrame)
-  , mRect(aLineLeft, aBStart, aISize, aBSize)
+  , mRect(aMarginRect.LineLeft(aWM, aContainerSize) + aLineLeft,
+          aMarginRect.BStart(aWM) + aBlockStart,
+          aMarginRect.ISize(aWM),
+          aMarginRect.BSize(aWM))
 {
   MOZ_COUNT_CTOR(nsFloatManager::FloatInfo);
 }
 
 #ifdef NS_BUILD_REFCNT_LOGGING
 nsFloatManager::FloatInfo::FloatInfo(const FloatInfo& aOther)
   : mFrame(aOther.mFrame),
     mLeftBEnd(aOther.mLeftBEnd),

--- a/layout/generic/nsFloatManager.h
+++ b/layout/generic/nsFloatManager.h
@@ -307,18 +307,19 @@ public:
 private:
 
   struct FloatInfo {
     nsIFrame *const mFrame;
     // The lowest block-ends of left/right floats up to and including
     // this one.
     nscoord mLeftBEnd, mRightBEnd;
 
-    FloatInfo(nsIFrame* aFrame, nscoord aLineLeft, nscoord aBStart,
-              nscoord aISize, nscoord aBSize);
+    FloatInfo(nsIFrame* aFrame, nscoord aLineLeft, nscoord aBlockStart,
+              const mozilla::LogicalRect& aMarginRect,
+              mozilla::WritingMode aWM, const nsSize& aContainerSize);
 
     nscoord LineLeft() const { return mRect.x; }
     nscoord LineRight() const { return mRect.XMost(); }
     nscoord ISize() const { return mRect.width; }
     nscoord BStart() const { return mRect.y; }
     nscoord BEnd() const { return mRect.YMost(); }
     nscoord BSize() const { return mRect.height; }
     bool IsEmpty() const { return mRect.IsEmpty(); }