Auto merge of #15175 - BorisChiou:animation/interpolate_and_cascade, r=heycam

Interpolate servo animation values and add them to the cascade

These are the servo-side changes for [bug 1317209](https://bugzilla.mozilla.org/show_bug.cgi?id=1317209). @Manishearth, @emilio, and @heycam have already reviewed them there. Please merge these patches until the gecko-side changes for [bug 1317209](https://bugzilla.mozilla.org/show_bug.cgi?id=1317209) is landed.

---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix [bug 1317209](https://bugzilla.mozilla.org/show_bug.cgi?id=1317209).
- [X] These changes do not require tests because there are existing tests for this in mozilla-central

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components/style/build_gecko.rs

@@ -491,6 +491,7 @@ mod bindings {
             "RawGeckoNode",
             "RawGeckoAnimationValueList",
             "RawServoAnimationValue",
+            "RawServoAnimationValueList",
             "RawGeckoPresContext",
             "RawGeckoPresContextOwned",
             "ThreadSafeURIHolder",
@@ -593,6 +594,7 @@ mod bindings {
         let servo_borrow_types = [
             "nsCSSValue",
             "RawGeckoAnimationValueList",
+            "RawServoAnimationValueList",
         ];
         for &ty in structs_types.iter() {
             builder = builder.hide_type(ty)