Add option to dump line box tree when dumping layout tree.

Source/platform/text/TextStream.cpp

Index: Source/platform/text/TextStream.cpp
diff --git a/Source/platform/text/TextStream.cpp b/Source/platform/text/TextStream.cpp
index 470eb2b9d523f03e5278564386d5511aa98bee91..41bc2545b740e1c574c58719f4aca15aa235e7d9 100644
--- a/Source/platform/text/TextStream.cpp
+++ b/Source/platform/text/TextStream.cpp
@@ -26,11 +26,15 @@
 #include "config.h"
 #include "platform/text/TextStream.h"
 
+#include "platform/LayoutUnit.h"
 #include "platform/geometry/FloatPoint.h"
 #include "platform/geometry/FloatRect.h"
 #include "platform/geometry/FloatSize.h"
 #include "platform/geometry/IntPoint.h"
 #include "platform/geometry/IntRect.h"
+#include "platform/geometry/LayoutPoint.h"
+#include "platform/geometry/LayoutRect.h"
+#include "platform/geometry/LayoutSize.h"
 #include "wtf/MathExtras.h"
 #include "wtf/StringExtras.h"
 #include "wtf/text/WTFString.h"
@@ -170,6 +174,27 @@ TextStream& operator<<(TextStream& ts, const FloatRect& r)
     return ts;
 }
 
+TextStream& operator<<(TextStream& ts, const LayoutUnit& unit)
+{
+    return ts << unit.toDouble();
+}
+
+TextStream& operator<<(TextStream& ts, const LayoutPoint& point)
+{
+    return ts << FloatPoint(point);
+}
+
+TextStream& operator<<(TextStream& ts, const LayoutRect& rect)
+{
+    return ts << FloatRect(rect);
+}
+
+TextStream& operator<<(TextStream& ts, const LayoutSize& size)
+{
+    return ts << FloatSize(size);
+}
+
+
 void writeIndent(TextStream& ts, int indent)
 {
     for (int i = 0; i != indent; ++i)