Support float widths in RenderTextHarfBuzz.

ui/gfx/render_text.h

Index: ui/gfx/render_text.h
diff --git a/ui/gfx/render_text.h b/ui/gfx/render_text.h
index f5cb746527ae697fb684406e1baed7376d870271..e5a17a1d1189a4d72876b1189141e83f21756abc 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -163,9 +163,8 @@ struct Line {
   // Segments that make up this line in visual order.
   std::vector<LineSegment> segments;
 
-  // A line size is the sum of segment widths and the maximum of segment
-  // heights.
-  Size size;
+  // The sum of segment widths and the maximum of segment heights.
+  SizeF size;
 
   // Sum of preceding lines' heights.
   int preceding_heights;