Bug 1696023: Report accessible's position even when bounds rect is empty r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D107001

accessible/ipc/other/DocAccessibleChild.cpp

@@ -1682,11 +1682,13 @@ mozilla::ipc::IPCResult DocAccessibleChild::RecvExtents(
         screenRect.y -= winCoords.y;
       }
 
-      *aX = screenRect.x;
-      *aY = screenRect.y;
       *aWidth = screenRect.width;
       *aHeight = screenRect.height;
     }
+    // We should always report the position of our acc, even if
+    // the returned screenRect is empty.
+    *aX = screenRect.x;
+    *aY = screenRect.y;
   }
   return IPC_OK();
 }
@@ -1702,11 +1704,13 @@ mozilla::ipc::IPCResult DocAccessibleChild::RecvExtentsInCSSPixels(
   if (acc && !acc->IsDefunct()) {
     nsIntRect screenRect = acc->BoundsInCSSPixels();
     if (!screenRect.IsEmpty()) {
-      *aX = screenRect.x;
-      *aY = screenRect.y;
       *aWidth = screenRect.width;
       *aHeight = screenRect.height;
     }
+    // We should always report the position of our acc, even if
+    // the returned screenRect is empty.
+    *aX = screenRect.x;
+    *aY = screenRect.y;
   }
   return IPC_OK();
 }

accessible/tests/browser/bounds/browser.ini

@@ -11,3 +11,4 @@ skip-if = e10s && os == 'win' # bug 1372296
 [browser_test_zoom.js]
 [browser_test_zoom_text.js]
 skip-if = e10s && os == 'win' # bug 1372296
+[browser_zero_area.js]

accessible/tests/browser/bounds/browser_zero_area.js

@@ -0,0 +1,37 @@
+/* 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, expectedWidth, expectedHeight) {
+  let [expectedX, expectedY] = 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);
+  is(height, expectedHeight, "Wrong height of " + prettyAccName);
+}
+
+/**
+ * Ensure frames with zero area have their x, y coordinates correctly reported
+ * in bounds()
+ */
+addAccessibleTask(
+  `
+<br>
+<div id="a" style="height:0; width:0;"></div>
+`,
+  async function(browser, accDoc) {
+    let a = findAccessibleChildByID(accDoc, "a");
+    await testContentBounds(browser, a, 0, 0);
+  }
+);