Fix invalid selection produced when dragging mouse outside the SVG text element

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

Index: third_party/WebKit/Source/core/layout/svg/LayoutSVGText.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/LayoutSVGText.cpp b/third_party/WebKit/Source/core/layout/svg/LayoutSVGText.cpp
index d5c12da2cdad6c98a2e8ff24bb65f5c1dd66ed28..22cffbd6544f8065a21bc62131f8ad2e5d6b17ab 100644
--- a/third_party/WebKit/Source/core/layout/svg/LayoutSVGText.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/LayoutSVGText.cpp
@@ -452,14 +452,17 @@ PositionWithAffinity LayoutSVGText::positionForPoint(const LayoutPoint& pointInC
     if (!rootBox)
         return createPositionWithAffinity(0);
 
+    LayoutPoint clippedPointInContents(pointInContents);
+    clippedPointInContents.clampNegativeToZero();
+
     ASSERT(!rootBox->nextRootBox());
     ASSERT(childrenInline());
 
-    InlineBox* closestBox = toSVGRootInlineBox(rootBox)->closestLeafChildForPosition(pointInContents);
+    InlineBox* closestBox = toSVGRootInlineBox(rootBox)->closestLeafChildForPosition(clippedPointInContents);
     if (!closestBox)
         return createPositionWithAffinity(0);
 
-    return closestBox->lineLayoutItem().positionForPoint(LayoutPoint(pointInContents.x(), closestBox->y()));
+    return closestBox->lineLayoutItem().positionForPoint(LayoutPoint(clippedPointInContents.x(), closestBox->y()));
 }
 
 void LayoutSVGText::absoluteQuads(Vector<FloatQuad>& quads, bool* wasFixed) const