1 files changed, 18 insertions, 8 deletions

diff --git a/Source/WebCore/rendering/RenderBlockFlow.cpp b/Source/WebCore/rendering/RenderBlockFlow.cpp
index 33bce4025..53ff0b6c7 100644
--- a/Source/WebCore/rendering/RenderBlockFlow.cpp
+++ b/Source/WebCore/rendering/RenderBlockFlow.cpp
@@ -1648,7 +1648,15 @@ static inline bool needsAppleMailPaginationQuirk(RootInlineBox& lineBox)
 
     return false;
 }
-    
+
+static void clearShouldBreakAtLineToAvoidWidowIfNeeded(RenderBlockFlow& blockFlow)
+{
+    if (!blockFlow.shouldBreakAtLineToAvoidWidow())
+        return;
+    blockFlow.clearShouldBreakAtLineToAvoidWidow();
+    blockFlow.setDidBreakAtLineToAvoidWidow();
+}
+
 void RenderBlockFlow::adjustLinePositionForPagination(RootInlineBox* lineBox, LayoutUnit& delta, bool& overflowsRegion, RenderFlowThread* flowThread)
 {
     // FIXME: Ignore anonymous inline blocks. Handle the delta already having been set because of
@@ -1702,8 +1710,11 @@ void RenderBlockFlow::adjustLinePositionForPagination(RootInlineBox* lineBox, La
         logicalBottom = intMinForLayoutUnit;
         lineBox->computeReplacedAndTextLineTopAndBottom(logicalOffset, logicalBottom);
         lineHeight = logicalBottom - logicalOffset;
-        if (logicalOffset == intMaxForLayoutUnit || lineHeight > pageLogicalHeight)
-            return; // Give up. We're genuinely too big even after excluding blank space and overflow.
+        if (logicalOffset == intMaxForLayoutUnit || lineHeight > pageLogicalHeight) {
+            // Give up. We're genuinely too big even after excluding blank space and overflow.
+            clearShouldBreakAtLineToAvoidWidowIfNeeded(*this);
+            return;
+        }
         pageLogicalHeight = pageLogicalHeightForOffset(logicalOffset);
     }
     
@@ -1712,10 +1723,8 @@ void RenderBlockFlow::adjustLinePositionForPagination(RootInlineBox* lineBox, La
 
     int lineIndex = lineCount(lineBox);
     if (remainingLogicalHeight < lineHeight || (shouldBreakAtLineToAvoidWidow() && lineBreakToAvoidWidow() == lineIndex)) {
-        if (shouldBreakAtLineToAvoidWidow() && lineBreakToAvoidWidow() == lineIndex) {
-            clearShouldBreakAtLineToAvoidWidow();
-            setDidBreakAtLineToAvoidWidow();
-        }
+        if (lineBreakToAvoidWidow() == lineIndex)
+            clearShouldBreakAtLineToAvoidWidowIfNeeded(*this);
         // If we have a non-uniform page height, then we have to shift further possibly.
         if (!hasUniformPageLogicalHeight && !pushToNextPageWithMinimumLogicalHeight(remainingLogicalHeight, logicalOffset, lineHeight))
             return;
@@ -3528,7 +3537,8 @@ bool RenderBlockFlow::relayoutForPagination(LayoutStateMaintainer& statePusher)
 
 bool RenderBlockFlow::hasLines() const
 {
-    ASSERT(childrenInline());
+    if (!childrenInline())
+        return false;
 
     if (auto simpleLineLayout = this->simpleLineLayout())
         return simpleLineLayout->lineCount();