For #6946 - Get engine margins without assuming top/bottom toolbar

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

@@ -593,7 +593,13 @@ abstract class BaseBrowserFragment : Fragment(), UserInteractionHandler, Session
     /**
      * Returns the top and bottom margins.
      */
-    protected abstract fun getEngineMargins(): Pair<Int, Int>
+    private fun getEngineMargins(): Pair<Int, Int> =
+        if (context?.settings()?.shouldUseBottomToolbar == true) {
+            val toolbarSize = resources.getDimensionPixelSize(R.dimen.browser_toolbar_height)
+            0 to toolbarSize
+        } else {
+            0 to 0
+        }
 
     /**
      * Returns the layout [android.view.Gravity] for the quick settings and ETP dialog.

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

@@ -190,11 +190,6 @@ class BrowserFragment : BaseBrowserFragment(), UserInteractionHandler {
         }
     }
 
-    override fun getEngineMargins(): Pair<Int, Int> {
-        val toolbarSize = resources.getDimensionPixelSize(R.dimen.browser_toolbar_height)
-        return 0 to toolbarSize
-    }
-
     private fun themeReaderViewControlsForPrivateMode(view: View) = with(view) {
         listOf(
             R.id.mozac_feature_readerview_font_size_decrease,

app/src/main/java/org/mozilla/fenix/customtabs/ExternalAppBrowserFragment.kt

@@ -71,7 +71,8 @@ class ExternalAppBrowserFragment : BaseBrowserFragment(), UserInteractionHandler
                         isPrivate = (activity as HomeActivity).browsingModeManager.mode.isPrivate
                     ),
                     owner = this,
-                    view = view)
+                    view = view
+                )
 
                 windowFeature.set(
                     feature = CustomTabWindowFeature(
@@ -186,11 +187,6 @@ class ExternalAppBrowserFragment : BaseBrowserFragment(), UserInteractionHandler
         }
     }
 
-    override fun getEngineMargins(): Pair<Int, Int> {
-        // Since the top toolbar is dynamic we don't want any margins
-        return 0 to 0
-    }
-
     override fun getContextMenuCandidates(
         context: Context,
         view: View