From 02b4894dcab0abb7b97d283e080a4ce8811e879e Mon Sep 17 00:00:00 2001
From: Morgan Reschenberg <mreschenberg@mozilla.com>
Date: Wed, 20 Oct 2021 14:49:14 +0000
Subject: [PATCH] Bug 1733440: Adjust RemoteAccessibleBase::Bounds for root
 relative coordinates r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D127848
---
 accessible/generic/LocalAccessible.cpp        | 34 +++++++++++--
 accessible/tests/browser/bounds/browser.ini   |  1 +
 .../bounds/browser_test_display_contents.js   | 48 +++++++++++++++++++
 3 files changed, 80 insertions(+), 3 deletions(-)
 create mode 100644 accessible/tests/browser/bounds/browser_test_display_contents.js

diff --git a/accessible/generic/LocalAccessible.cpp b/accessible/generic/LocalAccessible.cpp
index 6fa745d344de..38be6d1929eb 100644
--- a/accessible/generic/LocalAccessible.cpp
+++ b/accessible/generic/LocalAccessible.cpp
@@ -646,12 +646,40 @@ nsRect LocalAccessible::ParentRelativeBounds() {
       }
     }
 
-    if (mParent) {
-      boundingFrame = mParent->GetFrame();
+    // We need to find a frame to make our bounds relative to. We'll store this
+    // in `boundingFrame`. Ultimately, we'll create screen-relative coordinates
+    // by summing the x, y offsets of our ancestors' bounds in
+    // RemoteAccessibleBase::Bounds(), so it is important that our bounding
+    // frame have a corresponding accessible.
+    if (IsDoc() &&
+        nsCoreUtils::IsTopLevelContentDocInProcess(AsDoc()->DocumentNode())) {
+      // Tab documents and OOP iframe docs won't have ancestor accessibles with
+      // frames. We'll use their presshell root frame instead.
+      // XXX bug 1736635: Should DocAccessibles return their presShell frame on
+      // GetFrame()?
+      boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
+    }
+
+    // Iterate through ancestors to find one with a frame.
+    LocalAccessible* parent = mParent;
+    while (parent && !boundingFrame) {
+      if (parent->IsDoc()) {
+        // If we find a doc accessible, use its presshell's root frame
+        // (since doc accessibles themselves don't have frames).
+        boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
+        break;
+      }
+
+      if ((boundingFrame = parent->GetFrame())) {
+        // Otherwise, if the parent has a frame, use that
+        break;
+      }
+
+      parent = parent->LocalParent();
     }
 
     if (!boundingFrame) {
-      // if we can't get the bounding frame, use the pres shell root
+      MOZ_ASSERT_UNREACHABLE("No ancestor with frame?");
       boundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
     }
 
diff --git a/accessible/tests/browser/bounds/browser.ini b/accessible/tests/browser/bounds/browser.ini
index 4bd25fbefc8c..5b0fcc6d31ff 100644
--- a/accessible/tests/browser/bounds/browser.ini
+++ b/accessible/tests/browser/bounds/browser.ini
@@ -14,3 +14,4 @@ skip-if = webrender # Bug 1734271
 https_first_disabled = true
 skip-if = e10s && os == 'win' # bug 1372296
 [browser_zero_area.js]
+[browser_test_display_contents.js]
diff --git a/accessible/tests/browser/bounds/browser_test_display_contents.js b/accessible/tests/browser/bounds/browser_test_display_contents.js
new file mode 100644
index 000000000000..881eaa5c7ecc
--- /dev/null
+++ b/accessible/tests/browser/bounds/browser_test_display_contents.js
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/* import-globals-from ../../mochitest/layout.js */
+
+async function testContentBounds(browser, acc) {
+  let [
+    expectedX,
+    expectedY,
+    expectedWidth,
+    expectedHeight,
+  ] = await getContentBoundsForDOMElm(browser, getAccessibleDOMNodeID(acc));
+
+  let contentDPR = await getContentDPR(browser);
+  let [x, y, width, height] = getBounds(acc, contentDPR);
+  let prettyAccName = prettyName(acc);
+  is(x, expectedX, "Wrong x coordinate of " + prettyAccName);
+  is(y, expectedY, "Wrong y coordinate of " + prettyAccName);
+  is(width, expectedWidth, "Wrong width of " + prettyAccName);
+  ok(height >= expectedHeight, "Wrong height of " + prettyAccName);
+}
+
+async function runTests(browser, accDoc) {
+  let p = findAccessibleChildByID(accDoc, "div");
+  let p2 = findAccessibleChildByID(accDoc, "p");
+
+  await testContentBounds(browser, p);
+  await testContentBounds(browser, p2);
+}
+
+/**
+ * Test accessible bounds for accs with display:contents
+ */
+addAccessibleTask(
+  `
+  <div id="div">before
+    <ul id="ul" style="display: contents;">
+      <li id="li" style="display: contents;">
+        <p id="p">item</p>
+      </li>
+    </ul>
+  </div>`,
+  runTests,
+  { iframe: true, remoteIframe: true }
+);