third_party/WebKit/LayoutTests/accessibility/accessibility-node-memory-management.html

   1 <!DOCTYPE HTML>
   2 <html>
   3 <body>
   4 <script src="../resources/js-test.js"></script>
   5
   6 <canvas id="canvas" tabindex="-1"></canvas>
   7
   8 <div id="console"></div>
   9 <script>
  10 description("This test makes sure that AccessibilityNodeObjects are properly detached when the node they point to is deleted.");
  11
  12 if (window.testRunner && window.accessibilityController) {
  13     window.testRunner.dumpAsText();
  14
  15     // Create an ordinary button on the page, focus it and get its accessibility role.
  16     var button = document.createElement('button');
  17     document.body.appendChild(button);
  18     button.focus();
  19     window.axElement = accessibilityController.focusedElement;
  20     window.expectedButtonRole = axElement.role;
  21
  22     // Now remove the node from the tree and get the role of the detached accessibility object.
  23     document.body.removeChild(button);
  24     window.expectedDetachedRole = axElement.role;
  25     shouldBeTrue("expectedButtonRole != expectedDetachedRole");
  26
  27     // This time create a button that's a child of a canvas element. It will be focusable but not rendered.
  28     // In particular, this will create an AccessibilityNodeObject rather than an AccessibilityRenderObject.
  29     var canvas = document.getElementById('canvas');
  30     (function() {
  31         var button = document.createElement('button');
  32         canvas.appendChild(button);
  33
  34         // Note: focusing the button and using that to get its accessibility object creates an extra
  35         // reference to the button and it won't get deleted when we want it to. So instead we focus the
  36         // canvas and get its first child.
  37         canvas.focus();
  38         window.axElement = accessibilityController.focusedElement.childAtIndex(0);
  39
  40         window.canvasButtonRole = axElement.role;
  41         shouldBe("canvasButtonRole", "expectedButtonRole");
  42
  43         // Now delete the node.
  44         canvas.removeChild(button);
  45     })();
  46
  47     // Explicitly run garbage collection now; since there are no more references to the button,
  48     // the node will be destroyed.
  49     gc();
  50
  51     // Ensure that the accessibility object is detached by checking its role.
  52     window.detachedCanvasButtonRole = axElement.role;
  53     shouldBe("detachedCanvasButtonRole", "expectedDetachedRole");
  54 }
  55
  56 </script>
  57
  58 </body>
  59 </html>