fixes bug trullock#384 do not strip fr unit when reducing zeros; brow…

…sers don't animate changes to the grid-template-rows or grid-template-columns property when the unit changes from 1fr to 0.

src/NUglify.Tests/Css/Bugs.cs

@@ -172,5 +172,12 @@ public void Bug379()
 }
 ").Code);
         }
+
+        [Test]
+        public void Bug384()
+        {
+            var uglifyResult = Uglify.Css("grid-template-rows: 0fr 0px 0% 0em;");
+            Assert.AreEqual("grid-template-rows: 0fr 0 0% 0;", uglifyResult.Code);
+        }
     }
 }

src/NUglify/Css/CssScanner.cs

@@ -1086,7 +1086,6 @@ CssToken ScanNum(bool reduceZeros)
                             case "VM":          // viewport width or height, whichever is smaller of the two (use VMIN)
                             case "VMIN":        // minimum of the viewport's height and width
                             case "VMAX":        // maximum of the viewport's height and width
-                            case "FR":          // fraction of available space
                             case "GR":          // grid unit
                             case "GD":          // text grid unit
                                 tokenType = TokenType.RelativeLength;
@@ -1128,6 +1127,10 @@ CssToken ScanNum(bool reduceZeros)
                             case "ST":          // semitones
                                 tokenType = TokenType.Speech;
                                 break;
+                            // browsers do not animate grid-template-* if the fr unit is stripped
+                            case "FR":          // fraction of available space
+                                tokenType = TokenType.Dimension;
+                                break;
                         }
 
                         // if the number is zero, it really doesn't matter what the dimensions are so we can remove it