DevTools: format keys in object previews using sans serif.

third_party/WebKit/LayoutTests/inspector/console/console-dir-es6-expected.txt

 CONSOLE MESSAGE: line 15: [object Object]
 CONSOLE MESSAGE: line 18: Symbol()
 CONSOLE MESSAGE: line 22: [object Map]
 CONSOLE MESSAGE: line 22: [object WeakMap]
 CONSOLE MESSAGE: line 26: [object Set]
 CONSOLE MESSAGE: line 26: [object WeakSet]
 CONSOLE MESSAGE: line 34: [object Set]
 CONSOLE MESSAGE: line 37: [object WeakMap]
 CONSOLE MESSAGE: line 45: [object Map Iterator]
 CONSOLE MESSAGE: line 46: [object Map Iterator]
@@ skipping 93 matching lines @@
     [[IteratorHasMore]]: true
     [[IteratorIndex]]: 0
     [[IteratorKind]]: "entries"
     [[Entries]]: Array(1)
         0: Object
         length: 1
 console-dir-es6.html:85 Array(27)
     0: class 
     1: class classWithWhitespace
     2: class FooClass
-    3: function jump(x)
+    3: ƒ jump(x)
     4: class BarClass
     5: class BarClass2
     6: class BarClass3
     7: _ => { return 1 }
     8: (x) => { return 1 }
     9: (x, y, z) => { return 1 }
     10: ({}) => { return 1 }
     11: ([]) => { return 1 }
     12: () => { return "short" }
     13: () => {…}
     14: (...x) => { return 1 }
     15: (x, y, ...z) => { return 1 }
-    16: function (...x)
-    17: function (x, y, ...z)
-    18: function ({a})
-    19: function ([a])
-    20: function ({a, b})
-    21: function (...{a})
-    22: function (a = (1), b)
-    23: function (a = {x: (1)}, b)
-    24: function (a = (x) => { return 1 }, b)
-    25: function ({a: b})
-    26: function (c = ")", {a: b})
+    16: ƒ (...x)
+    17: ƒ (x, y, ...z)
+    18: ƒ ({a})
+    19: ƒ ([a])
+    20: ƒ ({a, b})
+    21: ƒ (...{a})
+    22: ƒ (a = (1), b)
+    23: ƒ (a = {x: (1)}, b)
+    24: ƒ (a = (x) => { return 1 }, b)
+    25: ƒ ({a: b})
+    26: ƒ (c = ")", {a: b})
     length: 27
     __proto__: Array(0)
 console-dir-es6.html:93 Array(4)
     0: badArrow(x = a => {…}
-    1: function (a = ")
-    2: function (a = function()
-    3: function (a = class{ constructor()
+    1: ƒ (a = ")
+    2: ƒ (a = function()
+    3: ƒ (a = class{ constructor()
     length: 4
     __proto__: Array(0)