Fix elevation for snackbar and fab

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

@@ -221,9 +221,7 @@ abstract class BaseBrowserFragment : Fragment(), UserInteractionHandler, Session
                             tabTrayDialog.dismiss()
                         }
 
-                        override fun onTabClosed(tab: Tab) {
-                            TODO("Not yet implemented")
-                        }
+                        override fun onTabClosed(tab: Tab) { /* noop */ }
 
                         override fun onNewTabTapped(private: Boolean) {
                             (activity as HomeActivity).browsingModeManager.mode = BrowsingMode.fromBoolean(private)

app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt

@@ -373,7 +373,7 @@ class HomeFragment : Fragment() {
                 }
 
                 override fun onTabClosed(tab: mozilla.components.concept.tabstray.Tab) {
-                    TODO("Not yet implemented")
+                    /* noop */
                 }
             }
         }

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

@@ -68,7 +68,6 @@ class TabTrayDialogFragment : AppCompatDialogFragment(), TabTrayInteractor {
     }
 
     override fun onTabClosed(tab: Tab) {
-        // interactor?.onTabClosed(tab)
         val sessionManager = view?.context?.components?.core?.sessionManager
         val snapshot = sessionManager
             ?.findSessionById(tab.id)?.let {
@@ -84,16 +83,18 @@ class TabTrayDialogFragment : AppCompatDialogFragment(), TabTrayInteractor {
             getString(R.string.snackbar_tab_closed)
         }
 
-        viewLifecycleOwner.lifecycleScope.allowUndo(
-            requireView(),
-            snackbarMessage,
-            getString(R.string.snackbar_deleted_undo),
-            {
-                sessionManager.add(snapshot.session, isSelected, engineSessionState = state)
-            },
-            operation = { },
-            anchorView = view?.handle
-        )
+        view?.tabLayout?.let {
+            viewLifecycleOwner.lifecycleScope.allowUndo(
+                it,
+                snackbarMessage,
+                getString(R.string.snackbar_deleted_undo),
+                {
+                    sessionManager.add(snapshot.session, isSelected, engineSessionState = state)
+                },
+                operation = { },
+                elevation = ELEVATION
+            )
+        }
     }
 
     override fun onTabSelected(tab: Tab) {
@@ -107,4 +108,8 @@ class TabTrayDialogFragment : AppCompatDialogFragment(), TabTrayInteractor {
     override fun onTabTrayDismissed() {
         dismissAllowingStateLoss()
     }
+
+    companion object {
+        private const val ELEVATION = 80f
+    }
 }

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

@@ -52,7 +52,7 @@ class TabTrayView(
 
         behavior.addBottomSheetCallback(object : BottomSheetBehavior.BottomSheetCallback() {
             override fun onSlide(bottomSheet: View, slideOffset: Float) {
-                if (slideOffset > SLIDE_OFFSET) {
+                if (slideOffset >= SLIDE_OFFSET) {
                     fabView.new_tab_button.show()
                 } else {
                     fabView.new_tab_button.hide()
@@ -120,7 +120,7 @@ class TabTrayView(
     companion object {
         private const val DEFAULT_TAB_ID = 0
         private const val PRIVATE_TAB_ID = 1
-        private const val SLIDE_OFFSET = 0.4
-        private const val ELEVATION = 41f
+        private const val SLIDE_OFFSET = 0
+        private const val ELEVATION = 90f
     }
 }

app/src/main/java/org/mozilla/fenix/utils/Undo.kt

@@ -36,7 +36,8 @@ fun CoroutineScope.allowUndo(
     undoActionTitle: String,
     onCancel: suspend () -> Unit = {},
     operation: suspend () -> Unit,
-    anchorView: View? = null
+    anchorView: View? = null,
+    elevation: Float? = null
 ) {
     // By using an AtomicBoolean, we achieve memory effects of reading and
     // writing a volatile variable.
@@ -58,6 +59,10 @@ fun CoroutineScope.allowUndo(
                 }
             }
 
+        elevation?.also {
+            snackbar.view.elevation = it
+        }
+
         snackbar.show()
 
         // Wait a bit, and if user didn't request cancellation, proceed with