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..05975e6a78eca425d69c055ef4262947297271bb 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -376,12 +376,15 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
   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 +419,9 @@ 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 +430,13 @@ 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 ([value isKindOfClass:[NSValue class]]) {
+    NSRange range = [value rangeValue];

[tapted, 2017/02/09 23:09:37]

I think we should only do this if data.action == ui::AX_ACTION_SET_SELECTION

NSValue might be used for other attributes, but it might not be an NSRange
that's stored there (but we can assume that if set data.action to
ui::AX_ACTION_SET_SELECTION above then this is what's in there).

[Patti Lor, 2017/02/13 23:31:03]

Done, thanks :)

+    data.anchor_offset = range.location;
+    data.focus_offset = range.location + range.length;
+  }
 
   if (data.action != ui::AX_ACTION_NONE)
     node_->GetDelegate()->AccessibilityPerformAction(data);