decrease header spacing from 32->28.

Previous spacing was based on applying the "full width" gutter spacing twice.

Signal/src/ViewControllers/ConversationView/Cells/OWSMessageCell.m

@@ -151,8 +151,8 @@ NS_ASSUME_NONNULL_BEGIN
         [self.contentView addSubview:self.headerView];
         [self.viewConstraints addObjectsFromArray:@[
             [self.headerView autoSetDimension:ALDimensionHeight toSize:headerHeight],
-            [self.headerView autoPinLeadingToSuperviewMarginWithInset:self.conversationStyle.fullWidthGutterLeading],
-            [self.headerView autoPinTrailingToSuperviewMarginWithInset:self.conversationStyle.fullWidthGutterTrailing],
+            [self.headerView autoPinLeadingToSuperviewMarginWithInset:self.conversationStyle.headerGutterLeading],
+            [self.headerView autoPinTrailingToSuperviewMarginWithInset:self.conversationStyle.headerGutterTrailing],
             [self.headerView autoPinEdgeToSuperviewEdge:ALEdgeTop],
             [self.messageBubbleView autoPinEdge:ALEdgeTop toEdge:ALEdgeBottom ofView:self.headerView],
         ]];

Signal/src/ViewControllers/ConversationView/Cells/OWSMessageHeaderView.m

@@ -93,8 +93,8 @@ const CGFloat OWSMessageHeaderViewDateHeaderVMargin = 23;
         [self.strokeView autoSetDimension:ALDimensionHeight toSize:strokeThickness],
 
         [self.stackView autoPinEdgeToSuperviewEdge:ALEdgeTop],
-        [self.stackView autoPinEdgeToSuperviewEdge:ALEdgeLeading withInset:conversationStyle.fullWidthGutterLeading],
-        [self.stackView autoPinEdgeToSuperviewEdge:ALEdgeTrailing withInset:conversationStyle.fullWidthGutterTrailing],
+        [self.stackView autoPinEdgeToSuperviewEdge:ALEdgeLeading],
+        [self.stackView autoPinEdgeToSuperviewEdge:ALEdgeTrailing],
     ];
 }
 

SignalMessaging/utils/ConversationStyle.swift

@@ -23,10 +23,15 @@ public class ConversationStyle: NSObject {
 
     @objc public var gutterLeading: CGFloat = 0
     @objc public var gutterTrailing: CGFloat = 0
+
+    @objc public var headerGutterLeading: CGFloat = 28
+    @objc public var headerGutterTrailing: CGFloat = 28
+
     // These are the gutters used by "full width" views
-    // like "date headers" and "unread indicator".
+    // like "contact offer" and "info message".
     @objc public var fullWidthGutterLeading: CGFloat = 0
     @objc public var fullWidthGutterTrailing: CGFloat = 0
+
     @objc public var errorGutterTrailing: CGFloat = 0
 
     // viewWidth - (gutterLeading + gutterTrailing)
@@ -88,6 +93,8 @@ public class ConversationStyle: NSObject {
         }
         fullWidthGutterLeading = 16
         fullWidthGutterTrailing = 16
+        headerGutterLeading = 28
+        headerGutterTrailing = 28
         errorGutterTrailing = 16
 
         contentWidth = viewWidth - (gutterLeading + gutterTrailing)