Revert "Calculate scroll view frame correctly" (#83)

* Revert "Stick the offset when height changes (#81)"

This reverts commit 41e1a67.

* Revert "Calculate scroll view frame correctly (#72)"

This reverts commit 5d30ee4.

Author: rnystrom

MessageViewController/MessageViewController.swift

@@ -129,12 +129,11 @@ open class MessageViewController: UIViewController, MessageAutocompleteControlle
         let originalOffset = scrollView.contentOffset
         let heightChange = scrollView.frame.height - messageViewFrame.minY
 
-        let frame = scrollView.frame
         scrollView.frame = CGRect(
-            x: frame.minX,
-            y: frame.minY,
-            width: frame.width,
-            height: messageViewFrame.minY - frame.minY
+            x: bounds.minX,
+            y: bounds.minY,
+            width: bounds.width,
+            height: messageViewFrame.minY
         )
 
         if updateOffset, heightChange != 0 {