Harmony - fix border for OIB.

ui/views/bubble/bubble_border.cc

Index: ui/views/bubble/bubble_border.cc
diff --git a/ui/views/bubble/bubble_border.cc b/ui/views/bubble/bubble_border.cc
index 182a3ffd2a24b9a43c49dabb8092521d2c544e9d..0cc3b3a0cda898cd441b7e09f78871cee1cf6975 100644
--- a/ui/views/bubble/bubble_border.cc
+++ b/ui/views/bubble/bubble_border.cc
@@ -507,7 +507,8 @@ void BubbleBackground::Paint(gfx::Canvas* canvas, views::View* view) const {
   gfx::RectF bounds(view->GetLocalBounds());
   bounds.Inset(gfx::InsetsF(border_->GetInsets()));
   if (UseMd()) {
-    // The border is 1px at all scale factors. Leave room for it.
+    // The border is 1px at all scale factors. Leave room for it. It's partially
+    // transparent, so we don't want to draw any background underneath it.
     const SkScalar one_pixel = SkFloatToScalar(1 / canvas->image_scale());
     bounds.Inset(gfx::InsetsF(one_pixel));
   }