Force accessibility tree layout when CSS transform changes

When a node's CSS transform changes, the accessibility tree should perform a layout so that focus appears in the correct location. R=dmazzoni@chromium.org, ikilpatrick@chromium.org Bug: 610840 Test: DumpAccessibilityTreeTest.AccessibilityTransform Change-Id: I2517358ea8f8b8a2b24c2daf358dca2058fe1c37 Reviewed-on: https://chromium-review.googlesource.com/1108393 Commit-Queue: James Wallace-Lee <jamwalla@chromium.org> Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org> Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org> Cr-Commit-Position: refs/heads/master@{#570135}

Force accessibility tree layout when CSS transform changes
When a node's CSS transform changes, the accessibility tree should perform a layout so that focus appears in the correct location. R=dmazzoni@chromium.org, ikilpatrick@chromium.org Bug: 610840 Test: DumpAccessibilityTreeTest.AccessibilityTransform Change-Id: I2517358ea8f8b8a2b24c2daf358dca2058fe1c37 Reviewed-on: https://chromium-review.googlesource.com/1108393 Commit-Queue: James Wallace-Lee <jamwalla@chromium.org> Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org> Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org> Cr-Commit-Position: refs/heads/master@{#570135}
ecbec4dd · James Wallace-Lee · Commit Bot · 3f54bc2f · ecbec4dd · ecbec4dd
Commit ecbec4dd authored Jun 25, 2018 by James Wallace-Lee Committed by Commit Bot Jun 25, 2018
7 changed files
--- a/content/browser/accessibility/dump_accessibility_tree_browsertest.cc
+++ b/content/browser/accessibility/dump_accessibility_tree_browsertest.cc
@@ -289,6 +289,10 @@ IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest,
  RunCSSTest(FILE_PATH_LITERAL("table-incomplete.html"));
 }

+IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityCSSTransform) {
+  RunCSSTest(FILE_PATH_LITERAL("transform.html"));
+}
+
 IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityA) {
  RunHtmlTest(FILE_PATH_LITERAL("a.html"));
 }

--- a/content/test/data/accessibility/css/transform-expected-blink.txt
+++ b/content/test/data/accessibility/css/transform-expected-blink.txt
+rootWebArea pageLocation=(0, 0)
++genericContainer pageLocation=(0, 0) name='Done'
++genericContainer pageLocation=(0, 50)
++++paragraph pageLocation=(0, 50)
++++++staticText pageLocation=(0, 50) name='content'
++++++++inlineTextBox pageLocation=(0, 50) name='content'
--- a/content/test/data/accessibility/css/transform.html
+++ b/content/test/data/accessibility/css/transform.html
+<!--
+
+@BLINK-ALLOW:pageLocation=(0, 0)
+@BLINK-ALLOW:pageLocation=(0, 50)
+@WAIT-FOR:Done
+-->
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+div, p {
+  margin: 0;
+  padding: 0;
+  border: 0;
+  top: 0;
+  left: 0;
+}
+div {
+  position: fixed;
+}
+#outer {
+    transform: TranslateY(2px);
+}
+</style>
+</head>
+<body>
+
+<div id="status" aria-label="Working"></div>
+<div id="outer">
+  <p>content</p>
+</div>
+
+<script>
+  setTimeout(function() {
+    document.getElementById("outer").style.transform = "translateY(50px)";
+  }, 10);
+  setTimeout(function() {
+    document.getElementById("status").setAttribute("aria-label", "Done");
+  }, 20);
+</script>
+</body>
+</html>
--- a/third_party/blink/renderer/core/dom/ax_object_cache.h
+++ b/third_party/blink/renderer/core/dom/ax_object_cache.h
@@ -67,6 +67,7 @@ class CORE_EXPORT AXObjectCache
  virtual void ListboxOptionStateChanged(HTMLOptionElement*) = 0;
  virtual void ListboxSelectedChildrenChanged(HTMLSelectElement*) = 0;
  virtual void ListboxActiveIndexChanged(HTMLSelectElement*) = 0;
+  virtual void LocationChanged(LayoutObject*) = 0;
  virtual void RadiobuttonRemovedFromGroup(HTMLInputElement*) = 0;

  virtual void Remove(AccessibleNode*) = 0;

--- a/third_party/blink/renderer/core/layout/layout_object.cc
+++ b/third_party/blink/renderer/core/layout/layout_object.cc
@@ -2126,6 +2126,11 @@ void LayoutObject::StyleWillChange(StyleDifference diff,
        cache->ChildrenChanged(Parent());
    }

+    if (diff.TransformChanged()) {
+      if (AXObjectCache* cache = GetDocument().ExistingAXObjectCache())
+        cache->LocationChanged(this);
+    }
+
    // Keep layer hierarchy visibility bits up to date if visibility changes.
    if (visibility_changed) {
      // We might not have an enclosing layer yet because we might not be in the

--- a/third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.cc
+++ b/third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.cc
@@ -822,6 +822,10 @@ void AXObjectCacheImpl::ListboxActiveIndexChanged(HTMLSelectElement* select) {
  ToAXListBox(obj)->ActiveIndexChanged();
 }

+void AXObjectCacheImpl::LocationChanged(LayoutObject* layout_object) {
+  PostNotification(layout_object, kAXLocationChanged);
+}
+
 void AXObjectCacheImpl::RadiobuttonRemovedFromGroup(
    HTMLInputElement* group_member) {
  AXObject* obj = Get(group_member);

--- a/third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.h
+++ b/third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.h
@@ -115,6 +115,7 @@ class MODULES_EXPORT AXObjectCacheImpl
  void ListboxOptionStateChanged(HTMLOptionElement*) override;
  void ListboxSelectedChildrenChanged(HTMLSelectElement*) override;
  void ListboxActiveIndexChanged(HTMLSelectElement*) override;
+  void LocationChanged(LayoutObject*) override;
  void RadiobuttonRemovedFromGroup(HTMLInputElement*) override;

  void Remove(AccessibleNode*) override;