MacViews/a11y: Allow accessibility clients to set new selections in Textfields.

ui/accessibility/platform/ax_platform_node_mac.mm

Index: ui/accessibility/platform/ax_platform_node_mac.mm
diff --git a/ui/accessibility/platform/ax_platform_node_mac.mm b/ui/accessibility/platform/ax_platform_node_mac.mm
index 5bfa69c675fa5c1124ea5fcf8954307ef461170f..cae3c2de2461ad4b2424d1cfe0dc14cd8edaaa35 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -370,18 +370,24 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
 }
 
 - (BOOL)accessibilityIsAttributeSettable:(NSString*)attributeName {
+  if (node_->GetData().HasStateFlag(ui::AX_STATE_DISABLED))
+    return NO;
+
   // Allow certain attributes to be written via an accessibility client. A
   // writable attribute will only appear as such if the accessibility element
   // has a value set for that attribute.
   if ([attributeName
           isEqualToString:NSAccessibilitySelectedChildrenAttribute] ||
       [attributeName
-          isEqualToString:NSAccessibilitySelectedTextRangeAttribute] ||
-      [attributeName
           isEqualToString:NSAccessibilityVisibleCharacterRangeAttribute]) {
     return NO;
   }
 
+  if ([attributeName
+          isEqualToString:NSAccessibilitySelectedTextRangeAttribute]) {
+    return YES;
+  }
+
   // Since tabs use the Radio Button role on Mac, the standard way to set them
   // is via the value attribute rather than the selected attribute.
   if ([attributeName isEqualToString:NSAccessibilityValueAttribute] &&
@@ -416,6 +422,9 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
                       : ui::AX_ACTION_SET_VALUE;
   } else if ([attribute isEqualToString:NSAccessibilitySelectedTextAttribute]) {
     data.action = ui::AX_ACTION_REPLACE_SELECTED_TEXT;
+  } else if ([attribute
+                 isEqualToString:NSAccessibilitySelectedTextRangeAttribute]) {
+    data.action = ui::AX_ACTION_SET_SELECTION;
   } else if ([attribute isEqualToString:NSAccessibilityFocusedAttribute]) {
     if ([value isKindOfClass:[NSNumber class]]) {
       data.action =
@@ -424,8 +433,14 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
   }
 
   // Set type-specific information as necessary for actions set above.
-  if ([value isKindOfClass:[NSString class]])
+  if ([value isKindOfClass:[NSString class]]) {
     data.value = base::SysNSStringToUTF16(value);
+  } else if (data.action == ui::AX_ACTION_SET_SELECTION &&
+             [value isKindOfClass:[NSValue class]]) {
+    NSRange range = [value rangeValue];
+    data.anchor_offset = range.location;
+    data.focus_offset = NSMaxRange(range);
+  }
 
   if (data.action != ui::AX_ACTION_NONE)
     node_->GetDelegate()->AccessibilityPerformAction(data);
@@ -488,17 +503,16 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
 }
 
 - (NSNumber*)AXEnabled {
-  return [NSNumber
-      numberWithBool:!ui::AXNodeData::IsFlagSet(node_->GetData().state,
-                                                ui::AX_STATE_DISABLED)];
+  return @(!ui::AXNodeData::IsFlagSet(node_->GetData().state,
+                                      ui::AX_STATE_DISABLED));
 }
 
 - (NSNumber*)AXFocused {
   if (ui::AXNodeData::IsFlagSet(node_->GetData().state,
                                 ui::AX_STATE_FOCUSABLE))
-    return [NSNumber numberWithBool:(node_->GetDelegate()->GetFocus() ==
-                                     node_->GetNativeViewAccessible())];
-  return [NSNumber numberWithBool:NO];
+    return
+        @(node_->GetDelegate()->GetFocus() == node_->GetNativeViewAccessible());
+  return @NO;
 }
 
 - (id)AXParent {
@@ -540,8 +554,7 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
 // Misc attributes.
 
 - (NSNumber*)AXSelected {
-  return [NSNumber
-      numberWithBool:node_->GetData().HasStateFlag(ui::AX_STATE_SELECTED)];
+  return @(node_->GetData().HasStateFlag(ui::AX_STATE_SELECTED));
 }
 
 - (NSString*)AXPlaceholderValue {
@@ -567,22 +580,20 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
   bool isReversed = (textDir == ui::AX_TEXT_DIRECTION_RTL) ||
                     (textDir == ui::AX_TEXT_DIRECTION_BTT);
   int beginSelectionIndex = (end > start && !isReversed) ? start : end;
-  return [NSValue
-      valueWithRange:NSMakeRange(beginSelectionIndex, abs(end - start))];
+  return [NSValue valueWithRange:{beginSelectionIndex, abs(end - start)}];
 }
 
 - (NSNumber*)AXNumberOfCharacters {
-  return [NSNumber numberWithInteger:[[self AXValue] length]];
+  return @([[self AXValue] length]);
 }
 
 - (NSValue*)AXVisibleCharacterRange {
-  return [NSValue
-      valueWithRange:NSMakeRange(0, [[self AXNumberOfCharacters] intValue])];
+  return [NSValue valueWithRange:{0, [[self AXNumberOfCharacters] intValue]}];
 }
 
 - (NSNumber*)AXInsertionPointLineNumber {
   // Multiline is not supported on views.
-  return [NSNumber numberWithInteger:0];
+  return @0;
 }
 
 @end