Message details shows entire message

When viewing a longer message, to avoid the risk of the user not being
aware they can scroll down, we scroll to the last couple lines of the
message, ensuring they can see the meta-data.

// FREEBIE

Signal/src/ViewControllers/MessageMetadataViewController.swift

@@ -25,6 +25,7 @@ class MessageMetadataViewController: OWSViewController {
     let databaseConnection: YapDatabaseConnection
 
     let bubbleFactory = OWSMessagesBubbleImageFactory()
+    var bubbleView: UIView?
 
     var message: TSMessage
 
@@ -69,6 +70,15 @@ class MessageMetadataViewController: OWSViewController {
 
         createViews()
 
+        self.view.layoutIfNeeded()
+        if let bubbleView = self.bubbleView {
+            let showAtLeast: CGFloat = 50
+            let middleCenter = CGPoint(x: bubbleView.frame.origin.x + bubbleView.frame.width / 2,
+                                       y: bubbleView.frame.origin.y + bubbleView.frame.height - showAtLeast)
+            let offset = bubbleView.superview!.convert(middleCenter, to: scrollView)
+            self.scrollView!.setContentOffset(offset, animated: false)
+        }
+
         NotificationCenter.default.addObserver(self,
             selector:#selector(yapDatabaseModified),
             name:NSNotification.Name.YapDatabaseModified,
@@ -283,8 +293,7 @@ class MessageMetadataViewController: OWSViewController {
                 bodyLabel.textColor = isIncoming ? UIColor.black : UIColor.white
                 bodyLabel.font = UIFont.ows_regularFont(withSize:16)
                 bodyLabel.text = messageBody
-                // Only show the first N lines.
-                bodyLabel.numberOfLines = 10
+                bodyLabel.numberOfLines = 0
                 bodyLabel.lineBreakMode = .byWordWrapping
 
                 let bubbleImageData = isIncoming ? bubbleFactory.incoming : bubbleFactory.outgoing
@@ -293,6 +302,7 @@ class MessageMetadataViewController: OWSViewController {
                 let trailingMargin: CGFloat = isIncoming ? 10 : 15
 
                 let bubbleView = UIImageView(image: bubbleImageData.messageBubbleImage)
+                self.bubbleView = bubbleView
 
                 bubbleView.layer.cornerRadius = 10
                 bubbleView.addSubview(bodyLabel)