Add check to InlineFlowBox::computeLogicalBoxHeights

third_party/WebKit/Source/core/layout/line/InlineFlowBox.cpp

Index: third_party/WebKit/Source/core/layout/line/InlineFlowBox.cpp
diff --git a/third_party/WebKit/Source/core/layout/line/InlineFlowBox.cpp b/third_party/WebKit/Source/core/layout/line/InlineFlowBox.cpp
index eb9eb22898eab695a7fd3048b6746f66b20d8241..6f3356be3c1c79648d61d078f6c7374d1c0eb4b8 100644
--- a/third_party/WebKit/Source/core/layout/line/InlineFlowBox.cpp
+++ b/third_party/WebKit/Source/core/layout/line/InlineFlowBox.cpp
@@ -588,6 +588,10 @@ void InlineFlowBox::computeLogicalBoxHeights(
   bool affectsDescent = false;
   bool checkChildren = !descendantsHaveSameLineHeightAndBaseline();
 
+  DCHECK(rootBox);
+  if (!rootBox)
+    return;
+
   if (isRootInlineBox()) {
     // Examine our root box.
     int ascent = 0;