Move m_lineBoxes and its getters down to LayoutBlockFlow.

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

Index: third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
index f9785333dca25a9433efe691cd30d9bf59de0dd9..632948e1b37e5d5aa19c878120a0debb5c802cb8 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
@@ -63,6 +63,14 @@ namespace blink {
 
 bool LayoutBlockFlow::s_canPropagateFloatIntoSibling = false;
 
+struct SameSizeAsLayoutBlockFlow : public LayoutBlock {
+    LineBoxList lineBoxes;
+    LayoutUnit m_paintInvalidationLogicalTopAndBottom[2];
+    void* pointers[2];
+};
+
+static_assert(sizeof(LayoutBlockFlow) == sizeof(SameSizeAsLayoutBlockFlow), "LayoutBlockFlow should stay small");
+
 struct SameSizeAsMarginInfo {
     uint16_t bitfields;
     LayoutUnit margins[2];