Do not crash when measuring empty SVG text nodes

third_party/WebKit/Source/core/layout/svg/SVGTextMetricsBuilder.cpp

Index: third_party/WebKit/Source/core/layout/svg/SVGTextMetricsBuilder.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/SVGTextMetricsBuilder.cpp b/third_party/WebKit/Source/core/layout/svg/SVGTextMetricsBuilder.cpp
index caabcbf1dfb00edb44535cf4e28a59edd3427c5d..6ada588e34942adb96f8735ea4f6cfe00a5d1426 100644
--- a/third_party/WebKit/Source/core/layout/svg/SVGTextMetricsBuilder.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/SVGTextMetricsBuilder.cpp
@@ -199,6 +199,9 @@ static void measureTextLayoutObject(LayoutSVGInlineText* text, MeasureTextData*
             textMetricsValues->clear();
     }
 
+    if (!text->textLength())
+        return;
+
     // TODO(pdr): This loop is too tightly coupled to SVGTextMetricsCalculator.
     // We should refactor SVGTextMetricsCalculator to be a simple bidi run
     // iterator and move all subrun logic to a single function.