Bug 1753251 - Treats twisty image in about:processes as a disclosure button. r=Jamie,florian

Summary row includes a Twisty image button to expand/collapse details - it is made focusable with keyboard, programmatic role of a `button` and a descriptive label are assigned, and keyboard events are provided. Related code is refactored and focus styling is updated.

Differential Revision: https://phabricator.services.mozilla.com/D139151

toolkit/components/aboutprocesses/content/aboutProcesses.css

@@ -131,7 +131,7 @@ td:not(:hover) > .profiler-icon:not(.profiler-active) {
   line-height: 50%;
   top: 4px; /* Half the image's height */
   inset-inline-start: -16px;
-  width: 100%;
+  width: 12px;
   -moz-context-properties: fill;
   fill: currentColor;
 }
@@ -141,6 +141,12 @@ td:not(:hover) > .profiler-icon:not(.profiler-active) {
 .twisty.open::before {
   content: url("chrome://global/skin/icons/arrow-down-12.svg");
 }
+.twisty:-moz-focusring {
+  outline: none;
+}
+.twisty:-moz-focusring::before {
+  outline: var(--in-content-focus-outline);
+}
 .indent {
   padding-inline: 48px 0;
 }

toolkit/components/aboutprocesses/content/aboutProcesses.js

@@ -587,6 +587,7 @@ var View = {
       }
       document.l10n.setAttributes(processNameElement, fluentName, fluentArgs);
       nameCell.className = ["type", "favicon", ...classNames].join(" ");
+      nameCell.setAttribute("id", data.pid + "-label");
 
       let image;
       switch (data.type) {
@@ -758,18 +759,27 @@ var View = {
     let span;
     if (!nameCell.firstChild) {
       nameCell.className = "name indent";
-      // Create the nodes
-      let img = document.createElement("span");
-      img.className = "twisty";
-      nameCell.appendChild(img);
+      // Create the nodes:
+      let imgBtn = document.createElement("span");
+      // Provide markup for an accessible disclosure button:
+      imgBtn.className = "twisty";
+      imgBtn.setAttribute("role", "button");
+      imgBtn.setAttribute("tabindex", "0");
+      // Label to include both summary and details texts
+      imgBtn.setAttribute("aria-labelledby", `${data.pid}-label ${rowId}`);
+      if (!imgBtn.hasAttribute("aria-expanded")) {
+        imgBtn.setAttribute("aria-expanded", "false");
+      }
+      nameCell.appendChild(imgBtn);
 
       span = document.createElement("span");
+      span.setAttribute("id", rowId);
       nameCell.appendChild(span);
     } else {
       // The only thing that can change is the thread count.
-      let img = nameCell.firstChild;
-      isOpen = img.classList.contains("open");
-      span = img.nextSibling;
+      let imgBtn = nameCell.firstChild;
+      isOpen = imgBtn.classList.contains("open");
+      span = imgBtn.nextSibling;
     }
     document.l10n.setAttributes(span, fluentName, fluentArgs);
 
@@ -1055,54 +1065,25 @@ var Control = {
 
     // Single click:
     // - show or hide the contents of a twisty;
+    // - close a process;
+    // - profile a process;
     // - change selection.
     tbody.addEventListener("click", event => {
       this._updateLastMouseEvent();
 
-      // Handle showing or hiding subitems of a row.
-      let target = event.target;
-      if (target.classList.contains("twisty")) {
-        this._handleTwisty(target);
-        return;
-      }
-      if (target.classList.contains("close-icon")) {
-        this._handleKill(target);
-        return;
-      }
+      this._handleActivate(event.target);
+    });
 
-      if (target.classList.contains("profiler-icon")) {
-        if (Services.profiler.IsActive()) {
-          return;
-        }
-        Services.profiler.StartProfiler(
-          10000000,
-          1,
-          ["default", "ipcmessages", "power"],
-          ["pid:" + target.parentNode.parentNode.process.pid]
-        );
-        target.classList.add("profiler-active");
-        setTimeout(() => {
-          ProfilerPopupBackground.captureProfile("aboutprofiling");
-          target.classList.remove("profiler-active");
-        }, PROFILE_DURATION * 1000);
-        return;
+    // Enter or Space keypress:
+    // - show or hide the contents of a twisty;
+    // - close a process;
+    // - profile a process;
+    // - change selection.
+    tbody.addEventListener("keypress", event => {
+      // Handle showing or hiding subitems of a row, when keyboard is used.
+      if (event.key === "Enter" || event.key === " ") {
+        this._handleActivate(event.target);
       }
-
-      // Handle selection changes
-      let row = target.closest("tr");
-      if (!row) {
-        return;
-      }
-      if (this.selectedRow) {
-        this.selectedRow.removeAttribute("selected");
-        if (this.selectedRow.rowId == row.rowId) {
-          // Clicking the same row again clears the selection.
-          this.selectedRow = null;
-          return;
-        }
-      }
-      row.setAttribute("selected", "true");
-      this.selectedRow = row;
     });
 
     // Double click:
@@ -1435,18 +1416,39 @@ var Control = {
     }
   },
 
+  // Handle events on image controls.
+  _handleActivate(target) {
+    if (target.classList.contains("twisty")) {
+      this._handleTwisty(target);
+      return;
+    }
+    if (target.classList.contains("close-icon")) {
+      this._handleKill(target);
+      return;
+    }
+
+    if (target.classList.contains("profiler-icon")) {
+      this._handleProfiling(target);
+      return;
+    }
+
+    this._handleSelection(target);
+  },
+
   // Open/close list of threads.
   _handleTwisty(target) {
     let row = target.parentNode.parentNode;
     if (target.classList.toggle("open")) {
+      target.setAttribute("aria-expanded", "true");
       this._showThreads(row, this._maxSlopeCpu);
       View.insertAfterRow(row);
     } else {
+      target.setAttribute("aria-expanded", "false");
       this._removeSubtree(row);
     }
   },
 
-  // Kill process/close tab/close subframe
+  // Kill process/close tab/close subframe.
   _handleKill(target) {
     let row = target.parentNode;
     if (row.process) {
@@ -1512,6 +1514,42 @@ var Control = {
       }
     }
   },
+
+  // Handle profiling of a process.
+  _handleProfiling(target) {
+    if (Services.profiler.IsActive()) {
+      return;
+    }
+    Services.profiler.StartProfiler(
+      10000000,
+      1,
+      ["default", "ipcmessages", "power"],
+      ["pid:" + target.parentNode.parentNode.process.pid]
+    );
+    target.classList.add("profiler-active");
+    setTimeout(() => {
+      ProfilerPopupBackground.captureProfile("aboutprofiling");
+      target.classList.remove("profiler-active");
+    }, PROFILE_DURATION * 1000);
+  },
+
+  // Handle selection changes.
+  _handleSelection(target) {
+    let row = target.closest("tr");
+    if (!row) {
+      return;
+    }
+    if (this.selectedRow) {
+      this.selectedRow.removeAttribute("selected");
+      if (this.selectedRow.rowId == row.rowId) {
+        // Clicking the same row again clears the selection.
+        this.selectedRow = null;
+        return;
+      }
+    }
+    row.setAttribute("selected", "true");
+    this.selectedRow = row;
+  },
 };
 
 window.onload = async function() {

toolkit/components/aboutprocesses/tests/browser/browser.ini

@@ -14,3 +14,4 @@ https_first_disabled = true
 [browser_aboutprocesses_show_frames_without_threads.js]
 https_first_disabled = true
 [browser_aboutprocesses_selection.js]
+[browser_aboutprocesses_twisty.js]

toolkit/components/aboutprocesses/tests/browser/browser_aboutprocesses_twisty.js

@@ -0,0 +1,132 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+let doc, tbody, tabAboutProcesses;
+
+const rowTypes = ["process", "window", "thread-summary", "thread"];
+
+function promiseUpdate() {
+  return promiseAboutProcessesUpdated({
+    doc,
+    tbody,
+    force: true,
+    tabAboutProcesses,
+  });
+}
+
+add_setup(async function() {
+  Services.prefs.setBoolPref("toolkit.aboutProcesses.showThreads", true);
+
+  info("Setting up about:processes");
+  tabAboutProcesses = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    opening: "about:processes",
+    waitForLoad: true,
+  });
+
+  doc = tabAboutProcesses.linkedBrowser.contentDocument;
+  tbody = doc.getElementById("process-tbody");
+  await promiseUpdate();
+});
+
+add_task(function testTwistyImageButtonSetup() {
+  let twistyBtn = doc.querySelector("tr.thread-summary .twisty");
+  let groupRow = twistyBtn.parentNode.parentNode;
+
+  info("Verify twisty button is properly set up.");
+  Assert.ok(
+    twistyBtn.hasAttribute("aria-labelledby"),
+    "the Twisty image button has an aria-labelledby"
+  );
+  Assert.equal(
+    twistyBtn.getAttribute("aria-labelledby"),
+    groupRow.firstChild.children[1].getAttribute("id"),
+    "the Twisty image button's aria-labelledby refers to a valid 'id' that is the Name of its row"
+  );
+  Assert.equal(
+    twistyBtn.getAttribute("role"),
+    "button",
+    "the Twisty image is programmatically a button"
+  );
+  Assert.equal(
+    twistyBtn.getAttribute("tabindex"),
+    "0",
+    "the Twisty image button is included in the focus order"
+  );
+  Assert.equal(
+    twistyBtn.getAttribute("aria-expanded"),
+    "false",
+    "the Twisty image button is collapsed by default"
+  );
+});
+
+add_task(function testTwistyImageButtonClicking() {
+  let twistyBtn = doc.querySelector("tr.thread-summary .twisty");
+  let groupRow = twistyBtn.parentNode.parentNode;
+
+  info(
+    "Verify we can toggle/open a list of threads by clicking the twisty button."
+  );
+  twistyBtn.click();
+
+  Assert.ok(
+    groupRow.nextSibling.classList.contains("thread") &&
+      !groupRow.nextSibling.classList.contains("thread-summary"),
+    "clicking a collapsed Twisty adds subitems after the row"
+  );
+  Assert.equal(
+    twistyBtn.getAttribute("aria-expanded"),
+    "true",
+    "the Twisty image button is expanded after a click"
+  );
+});
+
+add_task(function testTwistyImageButtonKeypressing() {
+  let twistyBtn = doc.querySelector("tr.thread-summary .twisty");
+  let groupRow = twistyBtn.parentNode.parentNode;
+
+  info(
+    `Verify we can toggle/close a list of threads by pressing Enter or
+    Space on the twisty button.`
+  );
+  // Verify the twisty button can be focused with a keyboard.
+  twistyBtn.focus();
+  Assert.equal(
+    twistyBtn,
+    doc.activeElement,
+    "the Twisty image button can be focused"
+  );
+
+  // Verify we can toggle subitems with a keyboard.
+  // Twisty is expanded
+  EventUtils.synthesizeKey("KEY_Enter");
+  Assert.ok(
+    !groupRow.nextSibling.classList.contains("thread") ||
+      groupRow.nextSibling.classList.contains("thread-summary"),
+    "pressing Enter on expanded Twisty hides a list of threads after the row"
+  );
+  Assert.equal(
+    twistyBtn.getAttribute("aria-expanded"),
+    "false",
+    "the Twisty image button is collapsed after an Enter keypress"
+  );
+  // Twisty is collapsed
+  EventUtils.synthesizeKey(" ");
+  Assert.ok(
+    groupRow.nextSibling.classList.contains("thread") &&
+      !groupRow.nextSibling.classList.contains("thread-summary"),
+    "pressing Space on collapsed Twisty shows a list of threads after the row"
+  );
+  Assert.equal(
+    twistyBtn.getAttribute("aria-expanded"),
+    "true",
+    "the Twisty image button is expanded after a Space keypress"
+  );
+});
+
+add_task(function cleanup() {
+  BrowserTestUtils.removeTab(tabAboutProcesses);
+  Services.prefs.clearUserPref("toolkit.aboutProcesses.showThreads");
+});