Creates AXPosition to uniquely identify a position in the accessibility tree

content/browser/accessibility/browser_accessibility_cocoa.mm

Index: content/browser/accessibility/browser_accessibility_cocoa.mm
diff --git a/content/browser/accessibility/browser_accessibility_cocoa.mm b/content/browser/accessibility/browser_accessibility_cocoa.mm
index a0a8338f3f294ec228f5613173c49785afc1e264..8145d818df1142cb9c930c45ac5ac36d513da30a 100644
--- a/content/browser/accessibility/browser_accessibility_cocoa.mm
+++ b/content/browser/accessibility/browser_accessibility_cocoa.mm
@@ -22,6 +22,8 @@
 #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;
@@ -94,13 +96,6 @@ 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;
 
@@ -139,11 +134,13 @@ AXTextMarkerRef AXTextMarkerRangeCopyEndMarker(
 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)));