Stop appending fragmentainer groups when flow thread offset approaches infinity.

third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.cpp

Index: third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.cpp b/third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.cpp
index c46732561903aa25bcb3343649e360bd5bf7a7e3..1f7f5a587362c7f48ddbff40d8c8edce312bb0ab 100644
--- a/third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.cpp
@@ -258,6 +258,11 @@ bool LayoutMultiColumnSet::needsNewFragmentainerGroupAt(
   if (!multiColumnFlowThread()->enclosingFragmentationContext())
     return false;
 
+  // If we have reached the limits of what a LayoutUnit can hold, we better
+  // stop, or we'd end up with zero-height columns.
+  if (offsetInFlowThread.mightBeSaturated())
+    return false;
+
   // We're in a nested fragmentation context, and the last fragmentainer group
   // cannot hold content at the specified offset without overflowing. This
   // usually warrants a new fragmentainer group; however, this will not be the