Improve appearance of focus rings at fractional scales.

ui/gfx/canvas.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_CANVAS_H_
 #define UI_GFX_CANVAS_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 406 matching lines @@
                                int flags);
 
   // Draws a dotted gray rectangle used for focus purposes.
   // DEPRECATED in favor of the RectF version below.
   // TODO(funkysidd): Remove this (http://crbug.com/553726)
   void DrawFocusRect(const Rect& rect);
 
   // 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.
   // Thus, |x| is 2 pixels if canvas scale = 2 & |x| = 1.
   void TileImageInt(const ImageSkia& image,
                     int x,
                     int y,
                     int w,
                     int h);
   void TileImageInt(const ImageSkia& image,
@@ skipping 72 matching lines @@
   // but surface_ will be null.
   sk_sp<cc::PaintSurface> surface_;
   cc::PaintCanvas* canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(Canvas);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_CANVAS_H_