Add missing imports to support building with Bazel

Author: thii

InAppViewDebugger/Element.swift

@@ -6,6 +6,7 @@
 //  Copyright © 2019 Indragie Karunaratne. All rights reserved.
 //
 
+import Foundation
 import CoreGraphics
 
 /// Provides identifying information for an element that is displayed in the

InAppViewDebugger/ParallelLineView.swift

@@ -6,7 +6,8 @@
 //  Copyright © 2019 Indragie Karunaratne. All rights reserved.
 //
 
-import Foundation
+import UIKit
+import CoreGraphics
 
 /// A view that draws one or more parallel vertical lines.
 final class ParallelLineView: UIView {

InAppViewDebugger/Snapshot.swift

@@ -7,6 +7,7 @@
 //
 
 import Foundation
+import CoreGraphics
 
 /// A snapshot of the UI element tree in its current state.
 @objc(IAVDSnapshot) public final class Snapshot: NSObject {