Avoid rebinding conversation items when pulsing them.

app/src/main/java/org/thoughtcrime/securesms/conversation/ConversationAdapterBridge.kt

@@ -17,6 +17,13 @@ interface ConversationAdapterBridge {
     const val PAYLOAD_NAME_COLORS = 1
     const val PAYLOAD_SELECTED = 2
     const val PAYLOAD_PARENT_SCROLLING = 3
+
+    /**
+     * The pulse highlight is rendered entirely by the item decoration, so items that receive this
+     * payload deliberately do nothing. It exists so that requesting a pulse does not force a full
+     * rebind of an item that is already on screen.
+     */
+    const val PAYLOAD_PULSE = 4
   }
 
   fun hasNoConversationMessages(): Boolean

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationAdapterV2.kt

@@ -272,7 +272,7 @@ class ConversationAdapterV2(
       if (recordToPulse != null) {
         pulseRequest = ConversationAdapterBridge.PulseRequest(position, recordToPulse!!.messageRecord.isOutgoing)
       }
-      notifyItemChanged(position)
+      notifyItemChanged(position, ConversationAdapterBridge.PAYLOAD_PULSE)
     }
   }
 
@@ -519,6 +519,10 @@ class ConversationAdapterV2(
         payloadApplied = true
       }
 
+      if (payload.contains(ConversationAdapterBridge.PAYLOAD_PULSE)) {
+        payloadApplied = true
+      }
+
       return payloadApplied
     }
 

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/items/V2ConversationItemTextOnlyViewHolder.kt

@@ -252,6 +252,10 @@ open class V2ConversationItemTextOnlyViewHolder<Model : MappingModel<Model>>(
       hasProcessedSupportedPayload = true
     }
 
+    if (ConversationAdapterBridge.PAYLOAD_PULSE in payload) {
+      hasProcessedSupportedPayload = true
+    }
+
     if (hasProcessedSupportedPayload && V2Payload.WALLPAPER !in payload) {
       return
     }