Ensure crop points are current

Previously setting the crop points via the text entry dialog would
update the sliders, but moving the sliders would not update the
pre-populated values in the text entry dialog. This was due to the text
field being populated with the `Trial` values, which aren't updated
until the crop changes are saved. This change uses the crop values from
the current playback view controller, which is the same value that the
sliders present and modify.

Fixes googlearchive#47

ScienceJournal/UI/CropRangeViewController.swift

@@ -37,7 +37,7 @@ class CropRangeViewController: UIViewController, EditTimestampViewControllerDele
   weak var delegate: CropRangeViewControllerDelegate?
 
   /// The crop range of the trial.
-  var trialCropRange: ChartAxis<Int64>?
+  private var trialCropRange: ChartAxis<Int64>?
 
   private var alertPresentation: TimestampAlertPresentation?
   private let trialRecordingRange: ChartAxis<Int64>
@@ -47,10 +47,8 @@ class CropRangeViewController: UIViewController, EditTimestampViewControllerDele
   /// Designated initializer
   ///
   /// - Parameters:
-  ///   - trialCropRange: The trial's crop range.
   ///   - trialRecordingRange: The trial's recording range.
-  init(trialCropRange: ChartAxis<Int64>?, trialRecordingRange: ChartAxis<Int64>) {
-    self.trialCropRange = trialCropRange
+  init(trialRecordingRange: ChartAxis<Int64>) {
     self.trialRecordingRange = trialRecordingRange
     cropValidator = CropValidator(trialRecordingRange: trialRecordingRange)
     super.init(nibName: nil, bundle: nil)
@@ -62,11 +60,12 @@ class CropRangeViewController: UIViewController, EditTimestampViewControllerDele
 
   /// Shows an alert that allows the user to manually input a timestamp for the given crop marker.
   ///
-  /// - Parameter marker: A crop marker type.
-  func showTimestampEditAlert(forCropMarkerType markerType: CropOverlayView.MarkerType) {
-    guard let trialCropRange = trialCropRange else {
-      return
-    }
+  /// - Parameters
+  ///   - trialCropRange: The trial's crop range.
+  ///   - markerType: A crop marker type.
+  func showTimestampEditAlert(forTrialCropRange trialCropRange: ChartAxis<Int64>,
+                              andCropMarkerType markerType: CropOverlayView.MarkerType) {
+    self.trialCropRange = trialCropRange
 
     let editTimestampVC = EditTimestampViewController()
     editTimestampVC.delegate = self

ScienceJournal/UI/TrialDetailViewController.swift

@@ -260,8 +260,7 @@ class TrialDetailViewController: MaterialHeaderViewController,
     self.preferenceManager = preferenceManager
     self.sensorDataManager = sensorDataManager
     cropValidator = CropValidator(trialRecordingRange: trial.recordingRange)
-    cropRangeController = CropRangeViewController(trialCropRange: trial.cropRange,
-                                                  trialRecordingRange: trial.recordingRange)
+    cropRangeController = CropRangeViewController(trialRecordingRange: trial.recordingRange)
 
     // MDCCollectionViewFlowLayout currently has a bug that breaks sectionHeadersPinToVisibleBounds
     // so we need to use a UICollectionViewFlowLayout instead until it's fixed. See issue:
@@ -1128,8 +1127,6 @@ class TrialDetailViewController: MaterialHeaderViewController,
                                         recordingRange: trial.recordingRange)
       }
     }
-
-    cropRangeController.trialCropRange = editingCropRange
   }
 
   private func endCropping() {
@@ -1296,17 +1293,25 @@ class TrialDetailViewController: MaterialHeaderViewController,
 
     // Edit start time.
     actions.append(PopUpMenuAction(title: String.editCropStartTime, isEnabled: true) { _ in
-      self.cropRangeController.showTimestampEditAlert(forCropMarkerType: .start)
+      self.showTimestampEditAlert(for: .start)
     })
 
     // Edit end time.
     actions.append(PopUpMenuAction(title: String.editCropEndTime, isEnabled: true) { _ in
-      self.cropRangeController.showTimestampEditAlert(forCropMarkerType: .end)
+      self.showTimestampEditAlert(for: .end)
     })
 
     return actions
   }
 
+  private func showTimestampEditAlert(for cropMarkerType: CropOverlayView.MarkerType) {
+    guard let trialCropRange = self.currentPlaybackViewController?.1.cropRange else {
+      return
+    }
+    self.cropRangeController.showTimestampEditAlert(forTrialCropRange: trialCropRange,
+                                                    andCropMarkerType: cropMarkerType)
+  }
+
   /// Creates trial data for export.
   ///
   /// - Parameter completion: Called when complete with a Bool indicating success, and the trial