--- a/layout/style/test/test_transitions_per_property.html
+++ b/layout/style/test/test_transitions_per_property.html
@@ -69,17 +69,16 @@ var skippedProperties = {
     "background-size": true,        // Bug 1387946
     "mask-position": true,          // Bug 1387946
     "mask-position-x": true,        // Bug 1387946
     "mask-position-y": true,        // Bug 1387946
     "mask-size": true,              // Bug 1387946
     "box-shadow": true,             // Bug 1387973
     "caret-color": true,            // Bug 1387951
     "clip": true,                   // Bug 1387951
-    "clip-path": true,              // Bug 1387952
     "column-count": true,           // Bug 1387939
     "-moz-image-region": true,      // Bug 1387951
     "order": true,                  // Bug 1387939
     "stroke-dasharray": true,       // Bug 1387986
     "stroke-dashoffset": true,      // Bug 1369614
     "stroke-width": true,           // Bug 1369614
     "text-shadow": true,            // Bug 1387973
     "vertical-align": true,         // Bug 1387949
@@ -682,42 +681,50 @@ var transformTests = [
 ];
 
 var clipPathTests = [
   { start: "none", end: "none",
     expected: ["none"] },
   // none to shape
   { start: "none",
     end: "circle(500px at 500px 500px) border-box",
-    expected: ["circle", ["500px at calc(500px + 0%) calc(500px + 0%)"], "border-box"]
+    expected:
+      isServo ? ["circle", ["500px at 500px 500px"], "border-box"]
+              : ["circle", ["500px at calc(500px + 0%) calc(500px + 0%)"], "border-box"]
   },
   { start: "none",
     end: "ellipse(500px 500px at 500px 500px) border-box",
-    expected: ["ellipse", ["500px 500px at calc(500px + 0%) calc(500px + 0%)"], "border-box"]
+    expected:
+      isServo ? ["ellipse", ["500px 500px at 500px 500px"], "border-box"]
+              : ["ellipse", ["500px 500px at calc(500px + 0%) calc(500px + 0%)"], "border-box"]
   },
   { start: "none",
     end: "polygon(evenodd, 500px 500px, 500px 500px) border-box",
     expected: ["polygon", ["evenodd, 500px 500px, 500px 500px"], "border-box"]
   },
   { start: "none",
     end: "inset(500px 500px 500px 500px round 500px 500px) border-box",
     expected: ["inset", ["500px round 500px"], "border-box"]
   },
   // matching functions
   { start: "circle(100px)", end: "circle(500px)",
     expected: ["circle", ["200px at 50% 50%"]] },
   { start: "ellipse(100px 100px)", end: "ellipse(500px 500px)",
     expected: ["ellipse", ["200px 200px at 50% 50%"]] },
   { start: "circle(100px at 100px 100px) border-box",
     end: "circle(500px at 500px 500px) border-box",
-    expected: ["circle", ["200px at calc(200px + 0%) calc(200px + 0%)"], "border-box"]
+    expected:
+      isServo ? ["circle", ["200px at 200px 200px"], "border-box"]
+              : ["circle", ["200px at calc(200px + 0%) calc(200px + 0%)"], "border-box"]
   },
   { start: "ellipse(100px 100px at 100px 100px) border-box",
     end: "ellipse(500px 500px at 500px 500px) border-box",
-    expected: ["ellipse", ["200px 200px at calc(200px + 0%) calc(200px + 0%)"], "border-box"]
+    expected:
+      isServo ? ["ellipse", ["200px 200px at 200px 200px"], "border-box"]
+              : ["ellipse", ["200px 200px at calc(200px + 0%) calc(200px + 0%)"], "border-box"]
   },
   { start: "polygon(evenodd, 100px 100px, 100px 100px) border-box",
     end: "polygon(evenodd, 500px 500px, 500px 500px) border-box",
     expected: ["polygon", ["evenodd, 200px 200px, 200px 200px"], "border-box"]
   },
   { start: "inset(100px 100px 100px 100px round 100px 100px) border-box",
     end: "inset(500px 500px 500px 500px round 500px 500px) border-box",
     expected: ["inset", ["200px round 200px"], "border-box"]
@@ -778,34 +785,40 @@ var clipPathTests = [
     expected: ["ellipse", ["500px 500px at 50% 50%"]] },
   { start: "ellipse(500px 500px)", end: "ellipse(farthest-side farthest-side)",
     expected: ["ellipse", ["farthest-side farthest-side at 50% 50%"]] },
   { start: "ellipse(500px 500px)", end: "ellipse(closest-side closest-side)",
     expected: ["ellipse", ["closest-side closest-side at 50% 50%"]] },
   // mismatching boxes
   { start: "circle(100px at 100px 100px) border-box",
     end: "circle(500px at 500px 500px) content-box",
-    expected: ["circle", ["500px at calc(500px + 0%) calc(500px + 0%)"], "content-box"]
+    expected:
+      isServo ? ["circle", ["500px at 500px 500px"], "content-box"]
+              : ["circle", ["500px at calc(500px + 0%) calc(500px + 0%)"], "content-box"]
   },
   { start: "ellipse(100px 100px at 100px 100px) border-box",
     end: "ellipse(500px 500px at 500px 500px) content-box",
-    expected: ["ellipse", ["500px 500px at calc(500px + 0%) calc(500px + 0%)"], "content-box"]
+    expected:
+      isServo ? ["ellipse", ["500px 500px at 500px 500px"], "content-box"]
+              : ["ellipse", ["500px 500px at calc(500px + 0%) calc(500px + 0%)"], "content-box"]
   },
   { start: "polygon(evenodd, 100px 100px, 100px 100px) border-box",
     end: "polygon(evenodd, 500px 500px, 500px 500px) content-box",
     expected: ["polygon", ["evenodd, 500px 500px, 500px 500px"], "content-box"]
   },
   { start: "inset(100px 100px 100px 100px round 100px 100px) border-box",
     end: "inset(500px 500px 500px 500px round 500px 500px) content-box",
     expected: ["inset", ["500px round 500px"], "content-box"]
   },
   // mismatching functions
   { start: "circle(100px at 100px 100px) border-box",
     end: "ellipse(500px 500px at 500px 500px) border-box",
-    expected: ["ellipse", ["500px 500px at calc(500px + 0%) calc(500px + 0%)"], "border-box"]
+    expected:
+      isServo ? ["ellipse", ["500px 500px at 500px 500px"], "border-box"]
+              : ["ellipse", ["500px 500px at calc(500px + 0%) calc(500px + 0%)"], "border-box"]
   },
   { start: "inset(0px round 20px)", end: "ellipse(500px 500px)",
     expected: ["ellipse", ["500px 500px at 50% 50%"]]
   },
   // shape to reference box
   { start: "circle(20px)", end: "content-box", expected: ["content-box"] },
   { start: "content-box", end: "circle(20px)", expected: ["circle", ["20px at 50% 50%"]] },
   // url to shape