For #19738 - Secure mode enabled in private tabs tray

Prevents screenshots while tabs tray with private tabs page is open.

app/src/main/java/org/mozilla/fenix/tabstray/SecureTabsTrayBinding.kt

@@ -0,0 +1,42 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.tabstray
+
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.map
+import mozilla.components.lib.state.helpers.AbstractBinding
+import mozilla.components.support.ktx.kotlinx.coroutines.flow.ifAnyChanged
+import org.mozilla.fenix.ext.removeSecure
+import org.mozilla.fenix.ext.secure
+import org.mozilla.fenix.utils.Settings
+
+/**
+ * Sets TabsTrayFragment flags to secure when private tabs list is selected.
+ */
+@OptIn(ExperimentalCoroutinesApi::class)
+class SecureTabsTrayBinding(
+    store: TabsTrayStore,
+    private val settings: Settings,
+    private val tabsTrayFragment: TabsTrayFragment
+) : AbstractBinding<TabsTrayState>(store) {
+
+    override suspend fun onState(flow: Flow<TabsTrayState>) {
+        flow.map { it }
+            .ifAnyChanged { state ->
+                arrayOf(
+                    state.selectedPage
+                )
+            }
+            .collect { state ->
+                if (state.selectedPage == Page.PrivateTabs) {
+                    tabsTrayFragment.secure()
+                } else if (!settings.lastKnownMode.isPrivate) {
+                    tabsTrayFragment.removeSecure()
+                }
+            }
+    }
+}

app/src/main/java/org/mozilla/fenix/tabstray/TabsTrayFragment.kt

@@ -72,6 +72,7 @@ class TabsTrayFragment : AppCompatDialogFragment() {
     private val selectionBannerBinding = ViewBoundFeatureWrapper<SelectionBannerBinding>()
     private val selectionHandleBinding = ViewBoundFeatureWrapper<SelectionHandleBinding>()
     private val tabsTrayCtaBinding = ViewBoundFeatureWrapper<TabsTrayInfoBannerBinding>()
+    private val secureTabsTrayBinding = ViewBoundFeatureWrapper<SecureTabsTrayBinding>()
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -267,6 +268,16 @@ class TabsTrayFragment : AppCompatDialogFragment() {
             owner = this,
             view = view
         )
+
+        secureTabsTrayBinding.set(
+            feature = SecureTabsTrayBinding(
+                store = tabsTrayStore,
+                settings = requireComponents.settings,
+                tabsTrayFragment = this
+            ),
+            owner = this,
+            view = view
+        )
     }
 
     @VisibleForTesting