[fenix] Closes https://github.com/mozilla-mobile/fenix/issues/16603: Disable pull down refresh when activity is in immersive mode (https://github.com/mozilla-mobile/fenix/pull/16793)

app/src/main/java/org/mozilla/fenix/browser/BaseBrowserFragment.kt

@@ -644,8 +644,8 @@ abstract class BaseBrowserFragment : Fragment(), UserInteractionHandler,
                     .collect { tab -> pipModeChanged(tab) }
             }
 
-            view.swipeRefresh.isEnabled =
-                FeatureFlags.pullToRefreshEnabled && context.settings().isPullToRefreshEnabledInBrowser
+            view.swipeRefresh.isEnabled = shouldPullToRefreshBeEnabled()
+
             if (view.swipeRefresh.isEnabled) {
                 val primaryTextColor =
                     ThemeManager.resolveAttribute(R.attr.primaryText, context)
@@ -771,6 +771,13 @@ abstract class BaseBrowserFragment : Fragment(), UserInteractionHandler,
         browserToolbarView.expand()
     }
 
+    @VisibleForTesting
+    internal fun shouldPullToRefreshBeEnabled(): Boolean {
+        return FeatureFlags.pullToRefreshEnabled &&
+                requireContext().settings().isPullToRefreshEnabledInBrowser &&
+                !(requireActivity() as HomeActivity).isImmersive
+    }
+
     private fun initializeEngineView(toolbarHeight: Int) {
         val context = requireContext()
 

app/src/test/java/org/mozilla/fenix/browser/BrowserFragmentTest.kt

@@ -38,6 +38,7 @@ import org.mozilla.fenix.R
 import org.mozilla.fenix.components.toolbar.BrowserToolbarView
 import org.mozilla.fenix.ext.application
 import org.mozilla.fenix.ext.components
+import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.helpers.FenixRobolectricTestRunner
 import org.mozilla.fenix.onboarding.FenixOnboarding
 
@@ -284,6 +285,26 @@ class BrowserFragmentTest {
         verify(exactly = 0) { onboarding.finish() }
     }
 
+    @Test
+    fun `WHEN isPullToRefreshEnabledInBrowser is disabled THEN pull down refresh is disabled`() {
+        every { homeActivity.isImmersive } returns false
+        every { context.settings().isPullToRefreshEnabledInBrowser } returns true
+        assert(browserFragment.shouldPullToRefreshBeEnabled())
+
+        every { context.settings().isPullToRefreshEnabledInBrowser } returns false
+        assert(!browserFragment.shouldPullToRefreshBeEnabled())
+    }
+
+    @Test
+    fun `WHEN in immersive mode THEN pull down refresh is disabled`() {
+        every { homeActivity.isImmersive } returns false
+        every { context.settings().isPullToRefreshEnabledInBrowser } returns true
+        assert(browserFragment.shouldPullToRefreshBeEnabled())
+
+        every { homeActivity.isImmersive } returns true
+        assert(!browserFragment.shouldPullToRefreshBeEnabled())
+    }
+
     private fun addAndSelectTab(tab: TabSessionState) {
         store.dispatch(TabListAction.AddTabAction(tab)).joinBlocking()
         store.dispatch(TabListAction.SelectTabAction(tab.id)).joinBlocking()