[css-grid] Implement fit-content track size

third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp

Index: third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
diff --git a/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp b/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
index ef1ab3cf7ccbbe200a8d81e6721fd1ec322a133f..bb03aff4a4b11e38d13b7b0e296b821ca1bd7f7b 100644
--- a/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
+++ b/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
@@ -720,11 +720,16 @@ static CSSValue* specifiedValueForGridTrackSize(const GridTrackSize& trackSize,
     switch (trackSize.type()) {
     case LengthTrackSizing:
         return specifiedValueForGridTrackBreadth(trackSize.length(), style);
-    case MinMaxTrackSizing:
-        CSSFunctionValue* minMaxTrackBreadths = CSSFunctionValue::create(CSSValueMinmax);
+    case MinMaxTrackSizing: {
+        auto* minMaxTrackBreadths = CSSFunctionValue::create(CSSValueMinmax);
         minMaxTrackBreadths->append(*specifiedValueForGridTrackBreadth(trackSize.minTrackBreadth(), style));
         minMaxTrackBreadths->append(*specifiedValueForGridTrackBreadth(trackSize.maxTrackBreadth(), style));
         return minMaxTrackBreadths;
+    } case FitContentTrackSizing: {
+        auto* fitContentTrackBreadth = CSSFunctionValue::create(CSSValueFitContent);
+        fitContentTrackBreadth->append(*specifiedValueForGridTrackBreadth(trackSize.length(), style));
+        return fitContentTrackBreadth;
+    }
     }
     ASSERT_NOT_REACHED();
     return nullptr;