1 files changed, 138 insertions, 0 deletions
diff --git a/gfx/layers/apz/test/mochitest/browser_test_scrollbar_in_extension_popup_window.js b/gfx/layers/apz/test/mochitest/browser_test_scrollbar_in_extension_popup_window.js
new file mode 100644
index 0000000000..6e18129845
--- /dev/null
+++ b/gfx/layers/apz/test/mochitest/browser_test_scrollbar_in_extension_popup_window.js
@@ -0,0 +1,138 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/browser/components/extensions/test/browser/head.js",
+  this
+);
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/browser/components/extensions/test/browser/head_browserAction.js",
+  this
+);
+
+add_task(async () => {
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      browser_action: {
+        default_popup: "popup.html",
+        browser_style: true,
+      },
+    },
+
+    files: {
+      "popup.html": `
+        <html>
+          <head>
+            <meta charset="utf-8">
+            <style>
+              * {
+                padding: 0;
+                margin: 0;
+              }
+              body {
+                height: 400px;
+                width: 200px;
+                overflow-y: auto;
+                overflow-x: hidden;
+              }
+              li {
+                display: flex;
+                justify-content: center;
+                align-items: center;
+                height: 30vh;
+                font-size: 200%;
+              }
+              li:nth-child(even){
+                background-color: #ccc;
+              }
+            </style>
+          </head>
+          <body>
+            <ul>
+              <li>1</li>
+              <li>2</li>
+              <li>3</li>
+              <li>4</li>
+              <li>5</li>
+              <li>6</li>
+              <li>7</li>
+              <li>8</li>
+              <li>9</li>
+              <li>10</li>
+            </ul>
+          </body>
+        </html>`,
+    },
+  });
+
+  await extension.startup();
+
+  async function takeSnapshot(browserWin) {
+    let browser = await openBrowserActionPanel(extension, browserWin, true);
+
+    // Ensure there's no pending paint requests.
+    // The below code is a simplified version of promiseAllPaintsDone in
+    // paint_listener.js.
+    await SpecialPowers.spawn(browser, [], async () => {
+      return new Promise(resolve => {
+        function waitForPaints() {
+          // Wait until paint suppression has ended
+          if (SpecialPowers.DOMWindowUtils.paintingSuppressed) {
+            dump`waiting for paint suppression to end...`;
+            content.window.setTimeout(waitForPaints, 0);
+            return;
+          }
+
+          if (SpecialPowers.DOMWindowUtils.isMozAfterPaintPending) {
+            dump`waiting for paint...`;
+            content.window.addEventListener("MozAfterPaint", waitForPaints, {
+              once: true,
+            });
+            return;
+          }
+          resolve();
+        }
+        waitForPaints();
+      });
+    });
+
+    const snapshot = await SpecialPowers.spawn(browser, [], async () => {
+      return SpecialPowers.snapshotWindowWithOptions(
+        content.window,
+        undefined /* use the default rect */,
+        undefined /* use the default bgcolor */,
+        { DRAWWINDOW_DRAW_VIEW: true } /* to capture scrollbars */
+      )
+        .toDataURL()
+        .toString();
+    });
+
+    const popup = getBrowserActionPopup(extension, browserWin);
+    await closeBrowserAction(extension, browserWin);
+    is(popup.state, "closed", "browserAction popup has been closed");
+
+    return snapshot;
+  }
+
+  // First, take a snapshot with disabling APZ in the popup window, we assume
+  // scrollbars are rendered properly there.
+  await SpecialPowers.pushPrefEnv({ set: [["apz.popups.enabled", false]] });
+  const newWin = await BrowserTestUtils.openNewBrowserWindow();
+  const reference = await takeSnapshot(newWin);
+  await BrowserTestUtils.closeWindow(newWin);
+
+  // Then take a snapshot with enabling APZ.
+  await SpecialPowers.pushPrefEnv({ set: [["apz.popups.enabled", true]] });
+  const anotherWin = await BrowserTestUtils.openNewBrowserWindow();
+  const test = await takeSnapshot(anotherWin);
+  await BrowserTestUtils.closeWindow(anotherWin);
+
+  is(
+    test,
+    reference,
+    "Contents in popup window opened by extension should be same regardless of the APZ state in the window"
+  );
+
+  await extension.unload();
+});