AX: Avoid unnecessary main-thread trip to get selectedTextRange() for…

… secure fields

https://bugs.webkit.org/show_bug.cgi?id=256407
rdar://problem/108977135

Reviewed by Chris Fleizach.

Secure fields always return an empty selected text range. Since we cache
AXPropertyName::IsSecureField, we can use this information to avoid a
main-thread hit.

* Source/WebCore/accessibility/AccessibilityObjectInterface.h:
(WebCore::AXCoreObject::shouldReturnEmptySelectedText const):
* Source/WebCore/accessibility/AccessibilityRenderObject.cpp:
(WebCore::AccessibilityRenderObject::selectedTextRange const):
* Source/WebCore/accessibility/isolatedtree/AXIsolatedObject.cpp:
(WebCore::AXIsolatedObject::selectedTextRange const):

Canonical link: https://commits.webkit.org/263762@main

Source/WebCore/accessibility/AccessibilityObjectInterface.h

@@ -1195,6 +1195,7 @@ class AXCoreObject : public ThreadSafeRefCounted<AXCoreObject> {
     virtual Path elementPath() const = 0;
     virtual bool supportsPath() const = 0;
 
+    bool shouldReturnEmptySelectedText() const { return isSecureField(); }
     virtual PlainTextRange selectedTextRange() const = 0;
     virtual int insertionPointLineNumber() const = 0;
 

Source/WebCore/accessibility/AccessibilityRenderObject.cpp

@@ -1389,8 +1389,8 @@ PlainTextRange AccessibilityRenderObject::selectedTextRange() const
 {
     ASSERT(isTextControl());
 
-    if (isSecureField())
-        return PlainTextRange();
+    if (shouldReturnEmptySelectedText())
+        return { };
 
     // Use the text control native range if it's a native object.
     if (isNativeTextControl()) {

Source/WebCore/accessibility/isolatedtree/AXIsolatedObject.cpp

@@ -1168,6 +1168,9 @@ bool AXIsolatedObject::isNativeTextControl() const
 
 PlainTextRange AXIsolatedObject::selectedTextRange() const
 {
+    if (shouldReturnEmptySelectedText())
+        return { };
+
     return Accessibility::retrieveValueFromMainThread<PlainTextRange>([this] () -> PlainTextRange {
         if (auto* object = associatedAXObject())
             return object->selectedTextRange();