Support keywords in LengthStyleInterpolation

LayoutTests/animations/interpolation/border-width-interpolation-expected.txt

Index: LayoutTests/animations/interpolation/border-width-interpolation-expected.txt
diff --git a/LayoutTests/animations/interpolation/border-width-interpolation-expected.txt b/LayoutTests/animations/interpolation/border-width-interpolation-expected.txt
index e0580a539902e801349a03ca2634712e4b09bbbb..51bfa9444682b7edc9803c7183137600244a2702 100644
--- a/LayoutTests/animations/interpolation/border-width-interpolation-expected.txt
+++ b/LayoutTests/animations/interpolation/border-width-interpolation-expected.txt
@@ -5,6 +5,34 @@ PASS: border-width from [0px] to [10px] was [3px] at 0.3
 PASS: border-width from [0px] to [10px] was [6px] at 0.6
 PASS: border-width from [0px] to [10px] was [10px] at 1
 PASS: border-width from [0px] to [10px] was [15px] at 1.5
+PASS: border-bottom-width from [thick] to [15px] was [0px] at -2
+PASS: border-bottom-width from [thick] to [15px] was [2px] at -0.3
+PASS: border-bottom-width from [thick] to [15px] was [5px] at 0
+PASS: border-bottom-width from [thick] to [15px] was [8px] at 0.3
+PASS: border-bottom-width from [thick] to [15px] was [11px] at 0.6
+PASS: border-bottom-width from [thick] to [15px] was [15px] at 1
+PASS: border-bottom-width from [thick] to [15px] was [20px] at 1.5
+PASS: border-left-width from [medium] to [13px] was [0px] at -2
+PASS: border-left-width from [medium] to [13px] was [0px] at -0.3
+PASS: border-left-width from [medium] to [13px] was [3px] at 0
+PASS: border-left-width from [medium] to [13px] was [6px] at 0.3
+PASS: border-left-width from [medium] to [13px] was [9px] at 0.6
+PASS: border-left-width from [medium] to [13px] was [13px] at 1
+PASS: border-left-width from [medium] to [13px] was [18px] at 1.5
+PASS: border-right-width from [thin] to [11px] was [0px] at -2
+PASS: border-right-width from [thin] to [11px] was [0px] at -0.3
+PASS: border-right-width from [thin] to [11px] was [1px] at 0
+PASS: border-right-width from [thin] to [11px] was [4px] at 0.3
+PASS: border-right-width from [thin] to [11px] was [7px] at 0.6
+PASS: border-right-width from [thin] to [11px] was [11px] at 1
+PASS: border-right-width from [thin] to [11px] was [16px] at 1.5
+PASS: border-top-width from [15px] to [thick] was [35px] at -2
+PASS: border-top-width from [15px] to [thick] was [18px] at -0.3
+PASS: border-top-width from [15px] to [thick] was [15px] at 0
+PASS: border-top-width from [15px] to [thick] was [12px] at 0.3
+PASS: border-top-width from [15px] to [thick] was [9px] at 0.6
+PASS: border-top-width from [15px] to [thick] was [5px] at 1
+PASS: border-top-width from [15px] to [thick] was [0px] at 1.5
 
 Web Animations API:
 PASS: borderWidth from [0px] to [10px] was [0px] at -0.3
@@ -13,4 +41,32 @@ PASS: borderWidth from [0px] to [10px] was [3px] at 0.3
 PASS: borderWidth from [0px] to [10px] was [6px] at 0.6
 PASS: borderWidth from [0px] to [10px] was [10px] at 1
 PASS: borderWidth from [0px] to [10px] was [15px] at 1.5
+PASS: borderBottomWidth from [thick] to [15px] was [0px] at -2
+PASS: borderBottomWidth from [thick] to [15px] was [2px] at -0.3
+PASS: borderBottomWidth from [thick] to [15px] was [5px] at 0
+PASS: borderBottomWidth from [thick] to [15px] was [8px] at 0.3
+PASS: borderBottomWidth from [thick] to [15px] was [11px] at 0.6
+PASS: borderBottomWidth from [thick] to [15px] was [15px] at 1
+PASS: borderBottomWidth from [thick] to [15px] was [20px] at 1.5
+PASS: borderLeftWidth from [medium] to [13px] was [0px] at -2
+PASS: borderLeftWidth from [medium] to [13px] was [0px] at -0.3
+PASS: borderLeftWidth from [medium] to [13px] was [3px] at 0
+PASS: borderLeftWidth from [medium] to [13px] was [6px] at 0.3
+PASS: borderLeftWidth from [medium] to [13px] was [9px] at 0.6
+PASS: borderLeftWidth from [medium] to [13px] was [13px] at 1
+PASS: borderLeftWidth from [medium] to [13px] was [18px] at 1.5
+PASS: borderRightWidth from [thin] to [11px] was [0px] at -2
+PASS: borderRightWidth from [thin] to [11px] was [0px] at -0.3
+PASS: borderRightWidth from [thin] to [11px] was [1px] at 0
+PASS: borderRightWidth from [thin] to [11px] was [4px] at 0.3
+PASS: borderRightWidth from [thin] to [11px] was [7px] at 0.6
+PASS: borderRightWidth from [thin] to [11px] was [11px] at 1
+PASS: borderRightWidth from [thin] to [11px] was [16px] at 1.5
+PASS: borderTopWidth from [15px] to [thick] was [35px] at -2
+PASS: borderTopWidth from [15px] to [thick] was [18px] at -0.3
+PASS: borderTopWidth from [15px] to [thick] was [15px] at 0
+PASS: borderTopWidth from [15px] to [thick] was [12px] at 0.3
+PASS: borderTopWidth from [15px] to [thick] was [9px] at 0.6
+PASS: borderTopWidth from [15px] to [thick] was [5px] at 1
+PASS: borderTopWidth from [15px] to [thick] was [0px] at 1.5