diff --git a/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleShapeView.h b/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleShapeView.h
index c6aca76a2..f05cc46fe 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleShapeView.h
+++ b/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleShapeView.h
@@ -8,6 +8,16 @@ NS_ASSUME_NONNULL_BEGIN
 
 @class OWSBubbleView;
 
+// While rendering message bubbles, we often need to render
+// into a subregion of the bubble that reflects the intersection
+// of some subview (e.g. a media view) and the bubble shape
+// (including its rounding).
+//
+// This view serves three different roles:
+//
+// * Drawing: Filling and/or stroking a subregion of the bubble shape.
+// * Shadows: Casting a shadow over a subregion of the bubble shape.
+// * Clipping: Clipping subviews to subregion of the bubble shape.
 @interface OWSBubbleShapeView : UIView <OWSBubbleViewPartner>
 
 @property (nonatomic, nullable) UIColor *fillColor;
diff --git a/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleView.h b/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleView.h
index a4d133dc1..bb1a9f4f1 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleView.h
+++ b/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleView.h
@@ -24,8 +24,6 @@ extern const CGFloat kOWSMessageCellCornerRadius;
 
 @property (nonatomic, nullable) UIColor *bubbleColor;
 
-@property (nonatomic, nullable, weak) id<OWSBubbleViewPartner> delegate;
-
 - (UIBezierPath *)maskPath;
 
 #pragma mark - Coordination
diff --git a/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleView.m b/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleView.m
index fd1f95d65..5ba4bde79 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleView.m
+++ b/Signal/src/ViewControllers/ConversationView/Cells/OWSBubbleView.m
@@ -160,7 +160,6 @@ const CGFloat kOWSMessageCellCornerRadius = 16;
     for (id<OWSBubbleViewPartner> partnerView in self.partnerViews) {
         [partnerView updateLayers];
     }
-    [self.delegate updateLayers];
 }
 
 + (CGFloat)minWidth