Decouples AOM float properties from the axtree

Due to changes in the API, AccessibleNode will no longer be able to
modify the underlying accessibility tree. For more information on the
motivations for this, see:

https://github.com/WICG/aom/blob/gh-pages/explainer.md#what-happened-to-accessiblenode

BUG=746523

Change-Id: I1b7b49fb04a62566295620e172e7d51078d6375f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1598897Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Meredith Lane <meredithl@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659309}

third_party/blink/renderer/core/aom/accessible_node.cc

@@ -447,10 +447,6 @@ float AccessibleNode::GetPropertyOrARIAAttribute(Element* element,
   if (!element)
     return 0.0;
 
-  float result = GetProperty(element, property, is_null);
-  if (!is_null)
-    return result;
-
   // Fall back on the equivalent ARIA attribute.
   QualifiedName attribute = GetCorrespondingARIAAttribute(property);
   AtomicString attr_value = element->FastGetAttribute(attribute);

third_party/blink/renderer/modules/accessibility/accessibility_object_model_test.cc

@@ -171,11 +171,11 @@ TEST_F(AccessibilityObjectModelTest, RangeProperties) {
   auto* ax_slider = cache->GetOrCreate(slider);
   float value = 0.0f;
   EXPECT_TRUE(ax_slider->MinValueForRange(&value));
-  EXPECT_EQ(-0.5f, value);
+  EXPECT_EQ(0.0f, value);
   EXPECT_TRUE(ax_slider->MaxValueForRange(&value));
-  EXPECT_EQ(0.5f, value);
+  EXPECT_EQ(100.0f, value);
   EXPECT_TRUE(ax_slider->ValueForRange(&value));
-  EXPECT_EQ(0.1f, value);
+  EXPECT_EQ(50.0f, value);
 }
 
 TEST_F(AccessibilityObjectModelTest, Level) {

third_party/blink/web_tests/accessibility/aom-float-properties.html

@@ -25,7 +25,7 @@ test(function(t) {
     assert_equals(axNode.intValue, 5);
     assert_equals(node.accessibleNode.valueNow, null);
     node.accessibleNode.valueNow = 9;
-    assert_equals(axNode.intValue, 9);
+    assert_equals(axNode.intValue, 5);
     node.accessibleNode.valueNow = null;
     assert_equals(axNode.intValue, 5);
     assert_equals(node.accessibleNode.valueNow, null);
@@ -44,8 +44,8 @@ test(function(t) {
     node.accessibleNode.valueNow = 33;
     node.accessibleNode.valueMin = -100;
     node.accessibleNode.valueMax = 100;;
-    assert_equals(axNode.intValue, 33);
-    assert_equals(axNode.minValue, -100);
+    assert_equals(axNode.intValue, 50);
+    assert_equals(axNode.minValue, 0);
     assert_equals(axNode.maxValue, 100);
 }, "Range values in accessible node of slider.");
 </script>
@@ -62,8 +62,8 @@ test(function(t) {
     node.accessibleNode.valueNow = 33;
     node.accessibleNode.valueMin = -100;
     node.accessibleNode.valueMax = 100;;
-    assert_equals(axNode.intValue, 33);
-    assert_equals(axNode.minValue, -100);
-    assert_equals(axNode.maxValue, 100);
+    assert_equals(axNode.intValue, 0);
+    assert_equals(axNode.minValue, 0);
+    assert_equals(axNode.maxValue, 0);
 }, "Range values in accessible node of spinbutton.");
 </script>