Merge commit '7621e2f8dec938cf48181c8b10afc9b01f444e68' into beta

submodules/lottie-ios/Sources/Private/MainThread/NodeRenderSystem/Protocols/RenderNode.swift

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+//
+//  RenderNode.swift
+//  lottie-swift
+//
+//  Created by Brandon Withrow on 1/17/19.
+//
+
+import CoreGraphics
+import Foundation
+import QuartzCore
+
+// MARK: - RenderNode
+
+/// A protocol that defines a node that holds render instructions
+protocol RenderNode {
+  var renderer: Renderable & NodeOutput { get }
+}
+
+// MARK: - Renderable
+
+/// A protocol that defines anything with render instructions
+protocol Renderable {
+
+  /// The last frame in which this node was updated.
+  var hasUpdate: Bool { get }
+
+  func hasRenderUpdates(_ forFrame: CGFloat) -> Bool
+
+  /// Determines if the renderer requires a custom context for drawing.
+  /// If yes the shape layer will perform a custom drawing pass.
+  /// If no the shape layer will be a standard CAShapeLayer
+  var shouldRenderInContext: Bool { get }
+
+  /// Passes in the CAShapeLayer to update
+  func updateShapeLayer(layer: CAShapeLayer)
+
+  /// Asks the renderer what the renderable bounds is for the given box.
+  func renderBoundsFor(_ boundingBox: CGRect) -> CGRect
+
+  /// Opportunity for renderers to inject sublayers
+  func setupSublayers(layer: CAShapeLayer)
+
+  /// Renders the shape in a custom context
+  func render(_ inContext: CGContext)
+}
+
+extension RenderNode where Self: AnimatorNode {
+
+  var outputNode: NodeOutput {
+    renderer
+  }
+
+}
+
+extension Renderable {
+
+  func renderBoundsFor(_ boundingBox: CGRect) -> CGRect {
+    /// Optional
+    boundingBox
+  }
+
+}