Remove unnecessary prefixes for gradient mixins given our stated brow…

…ser support.

twbs/bootstrap#11694

less/mixins.less

@@ -285,10 +285,8 @@
   // Creates two color stops, start and end, by specifying a color and position for each color stop.
   // Color stops are not available in IE9 and below.
   .horizontal(@start-color: #555; @end-color: #333; @start-percent: 0%; @end-percent: 100%) {
-    background-image: -webkit-gradient(linear, @start-percent top, @end-percent top, from(@start-color), to(@end-color)); // Safari 4+, Chrome 2+
-    background-image: -webkit-linear-gradient(left, color-stop(@start-color @start-percent), color-stop(@end-color @end-percent)); // Safari 5.1+, Chrome 10+
-    background-image: -moz-linear-gradient(left, @start-color @start-percent, @end-color @end-percent); // FF 3.6+
-    background-image:  linear-gradient(to right, @start-color @start-percent, @end-color @end-percent); // Standard, IE10
+    background-image: -webkit-linear-gradient(left, color-stop(@start-color @start-percent), color-stop(@end-color @end-percent)); // Safari 5.1-6, Chrome 10+
+    background-image:  linear-gradient(to right, @start-color @start-percent, @end-color @end-percent); // Standard, IE10, Firefox 16+, Opera 12.10+, Safari 7+, Chrome 26+
     background-repeat: repeat-x;
     filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=1)",argb(@start-color),argb(@end-color))); // IE9 and down
   }
@@ -298,47 +296,36 @@
   // Creates two color stops, start and end, by specifying a color and position for each color stop.
   // Color stops are not available in IE9 and below.
   .vertical(@start-color: #555; @end-color: #333; @start-percent: 0%; @end-percent: 100%) {
-    background-image: -webkit-gradient(linear, left @start-percent, left @end-percent, from(@start-color), to(@end-color)); // Safari 4+, Chrome 2+
-    background-image: -webkit-linear-gradient(top, @start-color, @start-percent, @end-color, @end-percent); // Safari 5.1+, Chrome 10+
-    background-image:  -moz-linear-gradient(top, @start-color @start-percent, @end-color @end-percent); // FF 3.6+
-    background-image: linear-gradient(to bottom, @start-color @start-percent, @end-color @end-percent); // Standard, IE10
+    background-image: -webkit-linear-gradient(top, @start-color @start-percent, @end-color @end-percent);  // Safari 5.1-6, Chrome 10+
+    background-image: linear-gradient(to bottom, @start-color @start-percent, @end-color @end-percent); // Standard, IE10, Firefox 16+, Opera 12.10+, Safari 7+, Chrome 26+
     background-repeat: repeat-x;
     filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",argb(@start-color),argb(@end-color))); // IE9 and down
   }
 
   .directional(@start-color: #555; @end-color: #333; @deg: 45deg) {
     background-repeat: repeat-x;
-    background-image: -webkit-linear-gradient(@deg, @start-color, @end-color); // Safari 5.1+, Chrome 10+
-    background-image: -moz-linear-gradient(@deg, @start-color, @end-color); // FF 3.6+
-    background-image: linear-gradient(@deg, @start-color, @end-color); // Standard, IE10
+    background-image: -webkit-linear-gradient(@deg, @start-color, @end-color); // Safari 5.1-6, Chrome 10+
+    background-image: linear-gradient(@deg, @start-color, @end-color); // Standard, IE10, Firefox 16+, Opera 12.10+, Safari 7+, Chrome 26+
   }
   .horizontal-three-colors(@start-color: #00b3ee; @mid-color: #7a43b6; @color-stop: 50%; @end-color: #c3325f) {
-    background-image: -webkit-gradient(left, linear, 0 0, 0 100%, from(@start-color), color-stop(@color-stop, @mid-color), to(@end-color));
     background-image: -webkit-linear-gradient(left, @start-color, @mid-color @color-stop, @end-color);
-    background-image: -moz-linear-gradient(left, @start-color, @mid-color @color-stop, @end-color);
     background-image: linear-gradient(to right, @start-color, @mid-color @color-stop, @end-color);
     background-repeat: no-repeat;
     filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=1)",argb(@start-color),argb(@end-color))); // IE9 and down, gets no color-stop at all for proper fallback
   }
   .vertical-three-colors(@start-color: #00b3ee; @mid-color: #7a43b6; @color-stop: 50%; @end-color: #c3325f) {
-    background-image: -webkit-gradient(linear, 0 0, 0 100%, from(@start-color), color-stop(@color-stop, @mid-color), to(@end-color));
     background-image: -webkit-linear-gradient(@start-color, @mid-color @color-stop, @end-color);
-    background-image: -moz-linear-gradient(top, @start-color, @mid-color @color-stop, @end-color);
     background-image: linear-gradient(@start-color, @mid-color @color-stop, @end-color);
     background-repeat: no-repeat;
     filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",argb(@start-color),argb(@end-color))); // IE9 and down, gets no color-stop at all for proper fallback
   }
   .radial(@inner-color: #555; @outer-color: #333) {
-    background-image: -webkit-gradient(radial, center center, 0, center center, 460, from(@inner-color), to(@outer-color));
     background-image: -webkit-radial-gradient(circle, @inner-color, @outer-color);
-    background-image: -moz-radial-gradient(circle, @inner-color, @outer-color);
     background-image: radial-gradient(circle, @inner-color, @outer-color);
     background-repeat: no-repeat;
   }
   .striped(@color: rgba(255,255,255,.15); @angle: 45deg) {
-    background-image: -webkit-gradient(linear, 0 100%, 100% 0, color-stop(.25, @color), color-stop(.25, transparent), color-stop(.5, transparent), color-stop(.5, @color), color-stop(.75, @color), color-stop(.75, transparent), to(transparent));
     background-image: -webkit-linear-gradient(@angle, @color 25%, transparent 25%, transparent 50%, @color 50%, @color 75%, transparent 75%, transparent);
-    background-image: -moz-linear-gradient(@angle, @color 25%, transparent 25%, transparent 50%, @color 50%, @color 75%, transparent 75%, transparent);
     background-image: linear-gradient(@angle, @color 25%, transparent 25%, transparent 50%, @color 50%, @color 75%, transparent 75%, transparent);
   }
 }