Add forEach() to CSSVariablesMap

LayoutTests/fast/css/variables/cssom-foreach-expected.txt

Index: LayoutTests/fast/css/variables/cssom-foreach-expected.txt
diff --git a/LayoutTests/fast/css/variables/cssom-foreach-expected.txt b/LayoutTests/fast/css/variables/cssom-foreach-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..d221bb4ae87c57aa42435c853b0b9de391da9f0f
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+++ b/LayoutTests/fast/css/variables/cssom-foreach-expected.txt
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+This tests basic calling of forEach on a CSSVariablesMap object.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS div.style.var.forEach() threw exception TypeError: Not enough arguments.
+PASS div.style.var.forEach("Not a function.") threw exception TypeError: Type error.
+
+Test calling forEach without thisArg specified:
+PASS log[0] is "[object CSSVariablesMap], a: apple, this == [object Window]"
+PASS log[1] is "[object CSSVariablesMap], b: banana, this == [object Window]"
+PASS log[2] is "[object CSSVariablesMap], c: carrot, this == [object Window]"
+PASS log.length is 3
+
+Test calling forEach with thisArg specified:
+PASS log[0] is "[object CSSVariablesMap], a: apple, this == {\"test\":\"pass\"}"
+PASS log[1] is "[object CSSVariablesMap], b: banana, this == {\"test\":\"pass\"}"
+PASS log[2] is "[object CSSVariablesMap], c: carrot, this == {\"test\":\"pass\"}"
+PASS log.length is 3
+
+PASS successfullyParsed is true
+
+TEST COMPLETE
+