Bug 1873948 - [webdriver-bidi] "browsingContext.close" should be able…

… to close the last tab of a window. r=webdriver-reviewers,Sasha

This also removes the custom value of the recommended
preference `browser.tabs.closeWindowWithLastTab` because
it's not needed anymore.

Differential Revision: https://phabricator.services.mozilla.com/D199134

remote/shared/RecommendedPreferences.sys.mjs

@@ -145,9 +145,6 @@ const COMMON_PREFERENCES = new Map([
   // Do not redirect user when a milstone upgrade of Firefox is detected
   ["browser.startup.homepage_override.mstone", "ignore"],
 
-  // Do not close the window when the last tab gets closed
-  ["browser.tabs.closeWindowWithLastTab", false],
-
   // Don't unload tabs when available memory is running low
   ["browser.tabs.unloadOnLowMemory", false],
 

remote/webdriver-bidi/modules/root/browsingContext.sys.mjs

@@ -17,7 +17,6 @@ ChromeUtils.defineESModuleGetters(lazy, {
   error: "chrome://remote/content/shared/webdriver/Errors.sys.mjs",
   EventPromise: "chrome://remote/content/shared/Sync.sys.mjs",
   getTimeoutMultiplier: "chrome://remote/content/shared/AppInfo.sys.mjs",
-  Log: "chrome://remote/content/shared/Log.sys.mjs",
   modal: "chrome://remote/content/shared/Prompt.sys.mjs",
   registerNavigationId:
     "chrome://remote/content/shared/NavigationManager.sys.mjs",
@@ -40,10 +39,6 @@ ChromeUtils.defineESModuleGetters(lazy, {
   windowManager: "chrome://remote/content/shared/WindowManager.sys.mjs",
 });
 
-ChromeUtils.defineLazyGetter(lazy, "logger", () =>
-  lazy.Log.get(lazy.Log.TYPES.WEBDRIVER_BIDI)
-);
-
 // Maximal window dimension allowed when emulating a viewport.
 const MAX_WINDOW_SIZE = 10000000;
 
@@ -415,11 +410,10 @@ class BrowsingContextModule extends Module {
     }
 
     if (lazy.TabManager.getTabCount() === 1) {
-      // The behavior when closing the last tab is currently unspecified.
-      // Warn the consumer about potential issues
-      lazy.logger.warn(
-        `Closing the last open tab (Browsing Context id ${contextId}), expect inconsistent behavior across platforms`
-      );
+      // The behavior when closing the very last tab is currently unspecified.
+      // As such behave like Marionette and don't allow closing it.
+      // See: https://github.com/w3c/webdriver-bidi/issues/187
+      return;
     }
 
     const tab = lazy.TabManager.getTabForBrowsingContext(context);

testing/web-platform/meta/webdriver/tests/bidi/browsing_context/close/close.py.ini

@@ -1,8 +1,3 @@
 [close.py]
   expected:
     if (processor == "x86") and not debug: [OK, TIMEOUT]
-  [test_top_level_context[window\]]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1873948
-    expected:
-      if os == "android": PASS
-      FAIL