Merge pull request #19235 from twbs/carousel-control-sm-up-width

Extract $carousel-control-sm-up-width variable

scss/_carousel.scss

@@ -225,16 +225,16 @@
   .carousel-control {
     .icon-prev,
     .icon-next {
-      width: 30px;
-      height: 30px;
-      margin-top: -15px;
-      font-size: 30px;
+      width: $carousel-control-sm-up-size;
+      height: $carousel-control-sm-up-size;
+      margin-top: -($carousel-control-sm-up-size / 2);
+      font-size: $carousel-control-sm-up-size;
     }
     .icon-prev {
-      margin-left: -15px;
+      margin-left: -($carousel-control-sm-up-size / 2);
     }
     .icon-next {
-      margin-right: -15px;
+      margin-right: -($carousel-control-sm-up-size / 2);
     }
   }
 

scss/_variables.scss

@@ -760,6 +760,7 @@ $carousel-text-shadow:                        0 1px 2px rgba(0,0,0,.6) !default;
 
 $carousel-control-color:                      #fff !default;
 $carousel-control-width:                      15% !default;
+$carousel-control-sm-up-size:                 30px !default;
 $carousel-control-opacity:                    .5 !default;
 $carousel-control-font-size:                  20px !default;