Improve appearance of focus rings at fractional scales.

ui/gfx/canvas.h

Index: ui/gfx/canvas.h
diff --git a/ui/gfx/canvas.h b/ui/gfx/canvas.h
index 4431261bb061bd108ce836d9c0d091df59f19f04..5c0f50d2d5f0dd4a9996b4f5a297197bc9ff222c 100644
--- a/ui/gfx/canvas.h
+++ b/ui/gfx/canvas.h
@@ -424,9 +424,10 @@ class GFX_EXPORT Canvas {
   // Draws a dotted gray rectangle used for focus purposes.
   void DrawFocusRect(const RectF& rect);
 
-  // Draws a |rect| in the specified region with the specified |color| with a
-  // with of one logical pixel which might be more device pixels.
-  void DrawSolidFocusRect(RectF rect, SkColor color, float thickness);
+  // Draws a |rect| in the specified region with the specified |color|. The
+  // width of the stroke is |thickness| dip, but the actual pixel width will be
+  // floored to ensure an integral value.
+  void DrawSolidFocusRect(RectF rect, SkColor color, int thickness);
 
   // Tiles the image in the specified region.
   // Parameters are specified relative to current canvas scale not in pixels.