Serialize font shorthand as empty string if any longhand is not specified

third_party/WebKit/LayoutTests/cssom/cssvalue-comparison.html

Index: third_party/WebKit/LayoutTests/cssom/cssvalue-comparison.html
diff --git a/third_party/WebKit/LayoutTests/cssom/cssvalue-comparison.html b/third_party/WebKit/LayoutTests/cssom/cssvalue-comparison.html
index 9835d4449d576e93210d33ea792c802296fa1933..e1516b25eae09ee4e2af4b3ac7494c2aac74631f 100644
--- a/third_party/WebKit/LayoutTests/cssom/cssvalue-comparison.html
+++ b/third_party/WebKit/LayoutTests/cssom/cssvalue-comparison.html
@@ -36,7 +36,6 @@ function run() {
    var tests = [ {"width" : ["20%", "2em", "2rem", "20px", "2cm", "20mm", "4in", "20pt", "10pc", "6vw", "6vh", "4vmin", "10vmax", "-webkit-calc(-100px + 100%)"]}, // lengths, calc
                   {"-webkit-transform" : ["rotate(15deg)", "rotate(1.55rad)", "rotate(200grad)", "rotate(0.5turn)"]}, // angle
                   {"background-image" : ["url(dummy://test.png)", "url(dummy://green.png)"]}, // uri
-                  {"font-weight" : ["bold", "inherit"]}, // ident
                   {"content" : ["counter(a)", "counters(a, '.')"]}, // counter
                   {"content" : ["attr(a)", "attr(p)"]}, // attr
                   {"clip" : ["rect(40px, 0, 45px, -5px)", "rect(10px, 5px, 15px, -10px)"]}, // rect
@@ -48,7 +47,13 @@ function run() {
                   {"border-image-source" : ["url(resources/greenbox.png)", "url(resources/redbox.png)"]}, // image
                   {"border-image-slice" : ["1 2 3 4", "2 3 4 5"]}, // border image slice
                   {"cursor" : ["url(resources/greenbox.png) 0 0, pointer", "url(resources/cursor.png) 1 1, wait"]}, // cursor
-                  {"font" : ["italic bold 12px/30px arial", "italic bold 8px/16px helvetica"]}, // font
+                  {"font-style" : ["italic", "oblique"]}, // font
+                  {"font-variant" : ["small-caps", "normal"]}, // font
+                  {"font-weight" : ["bold", "bolder"]}, // font
+                  {"font-stretch" : ["semi-condensed", "expanded"]}, // font
+                  {"font-size" : ["12px", "8px"]}, // font
+                  {"line-height" : ["30pz", "16px"]}, // font
+                  {"font-family" : ["arial", "helvetica"]}, // font
                   {"background-image" : ["-webkit-gradient(linear, left top, left bottom, from(#ccc), to(#000))", "-webkit-gradient(radial, 45 45, 0, 52 50, 0, from(#A7D30C), to(rgba(1,159,98,0)), color-stop(90%, #019F62))"]}, // gradients
                   {"background-image" : ["radial-gradient(circle, #ccc, #000)"]}, // gradients
                   {"background-image" : ["linear-gradient(#000, #234)", "linear-gradient(to top, #000, #234)"]}, // gradients