Move CAAnimation performer code to private/ sub-directory.

src/CAAnimationPlan.swift

@@ -27,35 +27,3 @@ extension CAAnimation: Plan {
     return CoreAnimationPerformer.self
   }
 }
-
-/** A light-weight Core Animation Material Motion performer. */
-class CoreAnimationPerformer: NSObject, PlanPerforming, ContinuousPerforming {
-  let target: CALayer
-  required init(target: Any) {
-    if let view = target as? UIView {
-      self.target = view.layer
-    } else {
-      self.target = target as! CALayer
-    }
-  }
-
-  func add(plan: Plan) {
-    let animation = plan as! CAAnimation
-
-    CATransaction.begin()
-
-    guard let token = tokenGenerator.generate() else { return }
-    CATransaction.setCompletionBlock {
-      token.terminate()
-    }
-
-    target.add(animation, forKey: nil)
-
-    CATransaction.commit()
-  }
-
-  var tokenGenerator: IsActiveTokenGenerating!
-  func set(isActiveTokenGenerator: IsActiveTokenGenerating) {
-    tokenGenerator = isActiveTokenGenerator
-  }
-}

src/private/CAAnimationPerformer.swift

@@ -0,0 +1,49 @@
+/*
+ Copyright 2016-present The Material Motion Authors. All Rights Reserved.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+import UIKit
+import MaterialMotionRuntime
+
+class CoreAnimationPerformer: NSObject, PlanPerforming, ContinuousPerforming {
+  let target: CALayer
+  required init(target: Any) {
+    if let view = target as? UIView {
+      self.target = view.layer
+    } else {
+      self.target = target as! CALayer
+    }
+  }
+
+  func add(plan: Plan) {
+    let animation = plan as! CAAnimation
+
+    CATransaction.begin()
+
+    guard let token = tokenGenerator.generate() else { return }
+    CATransaction.setCompletionBlock {
+      token.terminate()
+    }
+
+    target.add(animation, forKey: nil)
+
+    CATransaction.commit()
+  }
+
+  var tokenGenerator: IsActiveTokenGenerating!
+  func set(isActiveTokenGenerator: IsActiveTokenGenerating) {
+    tokenGenerator = isActiveTokenGenerator
+  }
+}