Bug 1769907 - Don't register desktop's SelectChild and SelectParent in GeckoView. r=geckoview-reviewers,agi

Actually, GeckoView registers both desktop and mobile actor for `<select>`
element. It is unnecessary to use desktop's `<select>` actor.

But, if GeckoView doesn't register desktop's `<select>` actor,
`layout/forms/test/test_select_reframe.html` will be failure since GV doesn't
handle `mozhidedropdown` that is a event when the control is unbinded from
layout tree.

So we need to handle this for this situation that is one of dismissed cases.

Differential Revision: https://phabricator.services.mozilla.com/D149526

mobile/android/components/geckoview/GeckoViewPrompt.jsm

@@ -160,6 +160,15 @@ class PromptFactory {
 
     const dismissPrompt = () => prompt.dismiss();
     aElement.addEventListener("blur", dismissPrompt, { mozSystemGroup: true });
+    const hidedropdown = event => {
+      if (aElement === event.target) {
+        prompt.dismiss();
+      }
+    };
+    const chromeEventHandler = aElement.ownerGlobal.docShell.chromeEventHandler;
+    chromeEventHandler.addEventListener("mozhidedropdown", hidedropdown, {
+      mozSystemGroup: true,
+    });
 
     prompt.asyncShowPrompt(
       {
@@ -173,6 +182,11 @@ class PromptFactory {
         aElement.removeEventListener("blur", dismissPrompt, {
           mozSystemGroup: true,
         });
+        chromeEventHandler.removeEventListener(
+          "mozhidedropdown",
+          hidedropdown,
+          { mozSystemGroup: true }
+        );
 
         if (aIsDropDown) {
           aElement.openInParentProcess = false;

toolkit/modules/ActorManagerParent.jsm

@@ -15,6 +15,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+const { AppConstants } = ChromeUtils.import(
+  "resource://gre/modules/AppConstants.jsm"
+);
 
 /**
  * Fission-compatible JSProcess implementations.
@@ -411,24 +414,6 @@ let JSWINDOWACTORS = {
     allFrames: true,
   },
 
-  Select: {
-    parent: {
-      moduleURI: "resource://gre/actors/SelectParent.jsm",
-    },
-
-    child: {
-      moduleURI: "resource://gre/actors/SelectChild.jsm",
-      events: {
-        mozshowdropdown: {},
-        "mozshowdropdown-sourcetouch": {},
-        mozhidedropdown: { mozSystemGroup: true },
-      },
-    },
-
-    includeChrome: true,
-    allFrames: true,
-  },
-
   // This actor is available for all pages that one can
   // view the source of, however it won't be created until a
   // request to view the source is made via the message
@@ -528,6 +513,29 @@ if (!Services.prefs.getBoolPref("browser.pagedata.enabled", false)) {
   };
 }
 
+/**
+ * Note that GeckoView has another implementation in mobile/android/actors.
+ */
+if (AppConstants.platform != "android") {
+  JSWINDOWACTORS.Select = {
+    parent: {
+      moduleURI: "resource://gre/actors/SelectParent.jsm",
+    },
+
+    child: {
+      moduleURI: "resource://gre/actors/SelectChild.jsm",
+      events: {
+        mozshowdropdown: {},
+        "mozshowdropdown-sourcetouch": {},
+        mozhidedropdown: { mozSystemGroup: true },
+      },
+    },
+
+    includeChrome: true,
+    allFrames: true,
+  };
+}
+
 var ActorManagerParent = {
   _addActors(actors, kind) {
     let register, unregister;