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

ui/accessibility/platform/ax_platform_node_mac.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ui/accessibility/platform/ax_platform_node_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
 #include "base/macros.h"
@@ skipping 358 matching lines @@
   return axAttributes.autorelease();
 }
 
 - (BOOL)accessibilityIsAttributeSettable:(NSString*)attributeName {
   // 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] &&
       node_->GetData().role == ui::AX_ROLE_TAB) {
     return !node_->GetData().HasStateFlag(ui::AX_STATE_SELECTED);
   }
 
   if ([attributeName isEqualToString:NSAccessibilityValueAttribute] ||
       [attributeName isEqualToString:NSAccessibilitySelectedTextAttribute]) {
     return !ui::AXNodeData::IsFlagSet(node_->GetData().state,
@@ skipping 14 matching lines @@
   ui::AXActionData data;
 
   // Check for attributes first. Only the |data.action| should be set here - any
   // type-specific information, if needed, should be set below.
   if ([attribute isEqualToString:NSAccessibilityValueAttribute]) {
     data.action = node_->GetData().role == ui::AX_ROLE_TAB
                       ? ui::AX_ACTION_SET_SELECTION
                       : 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 =
           [value boolValue] ? ui::AX_ACTION_FOCUS : ui::AX_ACTION_BLUR;
     }
   }
 
   // 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);
 
   // TODO(patricialor): Plumb through all the other writable attributes as
   // specified in accessibilityIsAttributeSettable.
 }
 
 - (id)accessibilityAttributeValue:(NSString*)attribute {
   SEL selector = NSSelectorFromString(attribute);
@@ skipping 192 matching lines @@
   }
   NotifyMacEvent(native_node_, event_type);
 }
 
 int AXPlatformNodeMac::GetIndexInParent() {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
   return -1;
 }
 
 }  // namespace ui