For #13117 - Hide save to collection button for private tabs in tab tray

app/src/main/java/org/mozilla/fenix/tabtray/SaveToCollectionsButtonAdapter.kt

@@ -32,6 +32,17 @@ class SaveToCollectionsButtonAdapter(
         return ViewHolder(itemView, interactor)
     }
 
+    override fun onBindViewHolder(holder: ViewHolder, position: Int, payloads: MutableList<Any>) {
+        if (payloads.isNullOrEmpty()) {
+            onBindViewHolder(holder, position)
+            return
+        }
+
+        (payloads[0] as TabTrayView.TabChange).let {
+            holder.itemView.isVisible = it == TabTrayView.TabChange.NORMAL
+        }
+    }
+
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
         holder.itemView.isVisible =
             interactor.onModeRequested() is TabTrayDialogFragmentState.Mode.Normal

app/src/main/java/org/mozilla/fenix/tabtray/TabTrayView.kt

@@ -233,9 +233,21 @@ class TabTrayView(
         behavior.state = BottomSheetBehavior.STATE_EXPANDED
     }
 
+    enum class TabChange {
+        PRIVATE, NORMAL
+    }
+
+    private fun toggleSaveToCollectionButton(isPrivate: Boolean) {
+        collectionsButtonAdapter.notifyItemChanged(
+            0,
+            if (isPrivate) TabChange.PRIVATE else TabChange.NORMAL
+        )
+    }
+
     override fun onTabSelected(tab: TabLayout.Tab?) {
         toggleFabText(isPrivateModeSelected)
         filterTabs.invoke(isPrivateModeSelected)
+        toggleSaveToCollectionButton(isPrivateModeSelected)
 
         updateUINormalMode(view.context.components.core.store.state)
         scrollToTab(view.context.components.core.store.state.selectedTabId)