Implemented SetSelection for the Web content on Windows.

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.
 
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 
 #include <execinfo.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
@@ skipping 941 matching lines @@
 }
 
 // Returns a text marker that points to the last character in the document that
 // can be selected with VoiceOver.
 - (id)endTextMarker {
   const BrowserAccessibility* root =
       browserAccessibility_->manager()->GetRoot();
   if (!root)
     return nil;
 
-  AXPlatformPositionInstance position =
-      CreateTextPosition(*root, 0, ui::AX_TEXT_AFFINITY_DOWNSTREAM);
+  AXPlatformPositionInstance position = root->CreatePositionAt(0);
   return CreateTextMarker(position->CreatePositionAtEndOfAnchor());
 }
 
 - (NSNumber*)expanded {
   if (![self instanceActive])
     return nil;
   return [NSNumber numberWithBool:
       GetState(browserAccessibility_, ui::AX_STATE_EXPANDED)];
 }
 
@@ skipping 738 matching lines @@
 }
 
 // Returns a text marker that points to the first character in the document that
 // can be selected with VoiceOver.
 - (id)startTextMarker {
   const BrowserAccessibility* root =
       browserAccessibility_->manager()->GetRoot();
   if (!root)
     return nil;
 
-  AXPlatformPositionInstance position =
-      CreateTextPosition(*root, 0, ui::AX_TEXT_AFFINITY_DOWNSTREAM);
+  AXPlatformPositionInstance position = root->CreatePositionAt(0);
   return CreateTextMarker(position->CreatePositionAtStartOfAnchor());
 }
 
 // Returns a subrole based upon the role.
 - (NSString*) subrole {
   if (![self instanceActive])
     return nil;
   ui::AXRole browserAccessibilityRole = [self internalRole];
   if (browserAccessibilityRole == ui::AX_ROLE_TEXT_FIELD &&
       GetState(browserAccessibility_, ui::AX_STATE_PROTECTED)) {
@@ skipping 387 matching lines @@
   if ([attribute isEqualToString:@"AXUIElementForTextMarker"]) {
     AXPlatformPositionInstance position =
         CreatePositionFromTextMarker(parameter);
     if (!position->IsNullPosition())
       return ToBrowserAccessibilityCocoa(position->GetAnchor());
 
     return nil;
   }
 
   if ([attribute isEqualToString:@"AXTextMarkerRangeForUIElement"]) {
-    AXPlatformPositionInstance startPosition = CreateTextPosition(
-        *browserAccessibility_, 0, ui::AX_TEXT_AFFINITY_DOWNSTREAM);
+    AXPlatformPositionInstance startPosition =
+        browser_accessibility_->CreatePositionAt(0);
     AXPlatformPositionInstance endPosition =
         startPosition->CreatePositionAtEndOfAnchor();
     AXPlatformRange range =
         AXPlatformRange(std::move(startPosition), std::move(endPosition));
     return CreateTextMarkerRange(std::move(range));
   }
 
   if ([attribute isEqualToString:@"AXStringForTextMarkerRange"])
     return GetTextForTextMarkerRange(parameter);
 
@@ skipping 674 matching lines @@
 }
 
 - (BOOL)accessibilityNotifiesWhenDestroyed {
   // Indicate that BrowserAccessibilityCocoa will post a notification when it's
   // destroyed (see -detach). This allows VoiceOver to do some internal things
   // more efficiently.
   return YES;
 }
 
 @end