Creates AXPosition to uniquely identify a position in the accessibility tree

content/browser/accessibility/browser_accessibility_cocoa.mm

 // Copyright (c) 2012 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.
 
 #include <execinfo.h>
 #include <stddef.h>
 #include <stdint.h>
 
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 
 #include <map>
 
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/strings/string16.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/app/strings/grit/content_strings.h"
 #include "content/browser/accessibility/browser_accessibility_mac.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/accessibility/browser_accessibility_manager_mac.h"
 #include "content/browser/accessibility/one_shot_accessibility_tree_search.h"
 #include "content/public/common/content_client.h"
 #include "third_party/skia/include/core/SkColor.h"
+#include "ui/accessibility/ax_position.h"
+#include "ui/accessibility/ax_range.h"
 #import "ui/accessibility/platform/ax_platform_node_mac.h"
 
 using content::AXTreeIDRegistry;
 using content::AccessibilityMatchPredicate;
 using content::BrowserAccessibility;
 using content::BrowserAccessibilityDelegate;
 using content::BrowserAccessibilityManager;
 using content::BrowserAccessibilityManagerMac;
 using content::ContentClient;
 using content::OneShotAccessibilityTreeSearch;
@@ skipping 52 matching lines @@
     @"AXTextMarkerRangeForUnorderedTextMarkers";
 NSString* const NSAccessibilityIndexForChildUIElementParameterizedAttribute =
     @"AXIndexForChildUIElement";
 
 // Actions.
 NSString* const NSAccessibilityScrollToVisibleAction = @"AXScrollToVisible";
 
 // A mapping from an accessibility attribute to its method name.
 NSDictionary* attributeToMethodNameMap = nil;
 
-struct AXTextMarkerData {
-  AXTreeIDRegistry::AXTreeID tree_id;
-  int32_t node_id;
-  int offset;
-  ui::AXTextAffinity affinity;
-};
-
 // VoiceOver uses -1 to mean "no limit" for AXResultsLimit.
 const int kAXResultsLimitNoLimit = -1;
 
 extern "C" {
 
 // See http://openradar.appspot.com/9896491. This SPI has been tested on 10.5,
 // 10.6, and 10.7. It allows accessibility clients to observe events posted on
 // this object.
 void NSAccessibilityUnregisterUniqueIdForUIElement(id element);
 
@@ skipping 18 matching lines @@
 AXTextMarkerRef AXTextMarkerRangeCopyEndMarker(
     AXTextMarkerRangeRef text_marker_range);
 
 #endif  // MAC_OS_X_VERSION_10_11
 
 }  // extern "C"
 
 id CreateTextMarker(const BrowserAccessibility& object,
                     int offset,
                     ui::AXTextAffinity affinity) {
-  AXTextMarkerData marker_data;
-  marker_data.tree_id = object.manager() ? object.manager()->ax_tree_id() : -1;
-  marker_data.node_id = object.GetId();
-  marker_data.offset = offset;
-  marker_data.affinity = affinity;
+  if (!object.instance_active())

[dmazzoni, 2016/10/03 18:22:51]

I think you should finish updating this file before we're
ready to check this in. It will be great proof that it
works.

+    return nil;
+
+  const auto manager = object.manager();
+  DCHECK(manager);
+  AXPosition marker_data = AXPlatformPosition::CreateTextPosition(manager->ax_tree_id(), object.node_id(), offset);

[dmazzoni, 2016/10/03 18:22:51]

Where is AXPlatformPosition::CreateTextPosition defined?

Also, a lot of functions in AXPosition return other
AXPositions. How are they going to return a
AXPlatformPosition? Are you going to use some sort
of factory?

+  marker_data.set_affinity(affinity);

[dmazzoni, 2016/10/03 18:22:51]

Don't you need an object of type AXPlatformPosition to do this?

   return (id)base::mac::CFTypeRefToNSObjectAutorelease(AXTextMarkerCreate(
       kCFAllocatorDefault, reinterpret_cast<const UInt8*>(&marker_data),
       sizeof(marker_data)));
 }
 
 id CreateTextMarkerRange(const BrowserAccessibility& start_object,
                          int start_offset,
                          ui::AXTextAffinity start_affinity,
                          const BrowserAccessibility& end_object,
                          int end_offset,
@@ skipping 2721 matching lines @@
   if (![self instanceActive])
     return [super hash];
   return browserAccessibility_->GetId();
 }
 
 - (BOOL)accessibilityShouldUseUniqueId {
   return YES;
 }
 
 @end