Implement support for special offset constants in IAccessibleText methods....

chrome/browser/accessibility/browser_accessibility_win.cc

 // Copyright (c) 2010 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 "chrome/browser/accessibility/browser_accessibility_win.h"
 
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/accessibility/browser_accessibility_manager_win.h"
@@ skipping 1205 matching lines @@
     return name_;
   }
 }
 
 LONG BrowserAccessibilityWin::FindBoundary(
     const string16& text,
     IA2TextBoundaryType boundary,
     LONG start_offset,
     LONG direction) {
   LONG text_size = static_cast<LONG>(text.size());
-  DCHECK(start_offset >= 0 && start_offset <= text_size);
+  DCHECK((start_offset >= 0 && start_offset <= text_size) ||
+         start_offset == IA2_TEXT_OFFSET_LENGTH ||
+         start_offset == IA2_TEXT_OFFSET_CARET);
   DCHECK(direction == 1 || direction == -1);
 
+  if (start_offset == IA2_TEXT_OFFSET_LENGTH) {
+    start_offset = text_size;
+  } else if (start_offset == IA2_TEXT_OFFSET_CARET) {
+    get_caretOffset(&start_offset);
+  }
+
   if (boundary == IA2_TEXT_BOUNDARY_CHAR) {
     if (direction == 1 && start_offset < text_size)
       return start_offset + 1;
     else
       return start_offset;
   }
 
   LONG result = start_offset;
   for (;;) {
     LONG pos;
@@ skipping 350 matching lines @@
   }
 
   // The role should always be set.
   DCHECK(!role_name_.empty() || ia_role_);
 
   // If we didn't explicitly set the IAccessible2 role, make it the same
   // as the MSAA role.
   if (!ia2_role_)
     ia2_role_ = ia_role_;
 }