From aa31799d78381d32070876dfaa3479eb1118eeaf Mon Sep 17 00:00:00 2001
From: Daisuke Akatsuka <daisuke@birchill.co.jp>
Date: Fri, 11 Dec 2020 23:52:20 +0000
Subject: [PATCH] Bug 1681217: Avoid sending keyup event to content document
 during cycling tabs. r=dao

Differential Revision: https://phabricator.services.mozilla.com/D98993
---
 browser/base/content/browser-ctrlTab.js       | 23 ++++++++++++-----
 .../content/test/general/browser_ctrlTab.js   | 25 +++++++++++++++++++
 2 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/browser/base/content/browser-ctrlTab.js b/browser/base/content/browser-ctrlTab.js
index de15801ab282..c05a474fd5ef 100644
--- a/browser/base/content/browser-ctrlTab.js
+++ b/browser/base/content/browser-ctrlTab.js
@@ -383,8 +383,6 @@ var ctrlTab = {
       return;
     }
 
-    document.addEventListener("keyup", this, true);
-
     this.canvasWidth = Math.ceil(
       (screen.availWidth * 0.85) / this.maxTabPreviews
     );
@@ -454,8 +452,6 @@ var ctrlTab = {
   },
 
   suspendGUI: function ctrlTab_suspendGUI() {
-    document.removeEventListener("keyup", this, true);
-
     for (let preview of this.previews) {
       this.updatePreview(preview, null);
     }
@@ -480,6 +476,8 @@ var ctrlTab = {
       return;
     }
 
+    Services.els.addSystemEventListener(document, "keyup", this, false);
+
     let tabs = gBrowser.visibleTabs;
     if (tabs.length > 2) {
       this.open();
@@ -584,8 +582,21 @@ var ctrlTab = {
         this.onKeyPress(event);
         break;
       case "keyup":
-        if (event.keyCode == event.DOM_VK_CONTROL) {
-          this.pick();
+        // During cycling tabs, we avoid sending keyup event to content document.
+        event.preventDefault();
+        event.stopPropagation();
+
+        if (event.keyCode === event.DOM_VK_CONTROL) {
+          Services.els.removeSystemEventListener(
+            document,
+            "keyup",
+            this,
+            false
+          );
+
+          if (this.isOpen) {
+            this.pick();
+          }
         }
         break;
       case "popupshowing":
diff --git a/browser/base/content/test/general/browser_ctrlTab.js b/browser/base/content/test/general/browser_ctrlTab.js
index b3c495ab7828..b31b971315d9 100644
--- a/browser/base/content/test/general/browser_ctrlTab.js
+++ b/browser/base/content/test/general/browser_ctrlTab.js
@@ -211,6 +211,17 @@ add_task(async function() {
         ? "back to the previously selected tab"
         : normalized + " tabs back in most-recently-selected order";
 
+    // Add keyup listener to all content documents.
+    await Promise.all(
+      gBrowser.tabs.map(tab =>
+        SpecialPowers.spawn(tab.linkedBrowser, [], () => {
+          content.window.addEventListener("keyup", () => {
+            content.window._ctrlTabTestKeyupHappend = true;
+          });
+        })
+      )
+    );
+
     for (let i = 0; i < tabTimes; i++) {
       await pressCtrlTab();
 
@@ -253,5 +264,19 @@ add_task(async function() {
         " goes " +
         where
     );
+
+    const keyupEvents = await Promise.all(
+      gBrowser.tabs.map(tab =>
+        SpecialPowers.spawn(
+          tab.linkedBrowser,
+          [],
+          () => !!content.window._ctrlTabTestKeyupHappend
+        )
+      )
+    );
+    ok(
+      keyupEvents.every(isKeyupHappned => !isKeyupHappned),
+      "Content document doesn't capture Keyup event during cycling tabs"
+    );
   }
 });