Fix Views overlay scrollbar border stroke.

ui/views/controls/scrollbar/overlay_scroll_bar.cc

 // Copyright 2013 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.
 
 #include "ui/views/controls/scrollbar/overlay_scroll_bar.h"
 
 #include "base/macros.h"
 #include "cc/paint/paint_flags.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
@@ skipping 49 matching lines @@
                                  IsHorizontal() ? 0 : kThumbHoverOffset, 0, 0));
   fill_bounds.Inset(gfx::InsetsF(kThumbStroke, kThumbStroke,
                                  IsHorizontal() ? 0 : kThumbStroke,
                                  IsHorizontal() ? kThumbStroke : 0));
   canvas->DrawRect(fill_bounds, fill_flags);
 
   cc::PaintFlags stroke_flags;
   stroke_flags.setStyle(cc::PaintFlags::kStroke_Style);
   stroke_flags.setColor(SK_ColorWHITE);
   stroke_flags.setStrokeWidth(kThumbStroke);
+  stroke_flags.setStrokeCap(cc::PaintFlags::kSquare_Cap);
   gfx::RectF stroke_bounds(fill_bounds);
   stroke_bounds.Inset(gfx::InsetsF(kThumbStroke / 2.f));
   // The stroke doesn't apply to the far edge of the thumb.
   SkPath path;
   path.moveTo(gfx::PointFToSkPoint(stroke_bounds.top_right()));
   path.lineTo(gfx::PointFToSkPoint(stroke_bounds.origin()));
   path.lineTo(gfx::PointFToSkPoint(stroke_bounds.bottom_left()));
   if (IsHorizontal()) {
     path.moveTo(gfx::PointFToSkPoint(stroke_bounds.bottom_right()));
     path.close();
@@ skipping 91 matching lines @@
 
 void OverlayScrollBar::StartHideCountdown() {
   if (IsMouseHovered())
     return;
   hide_timer_.Start(
       FROM_HERE, base::TimeDelta::FromSeconds(1),
       base::Bind(&OverlayScrollBar::Hide, base::Unretained(this)));
 }
 
 }  // namespace views