Re-land: Send Windows accessibility events based on tree updates.

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>
 
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 
 #include <map>
 
@@ skipping 464 matching lines @@
 - (NSString*)orientation {
   if (GetState(browserAccessibility_, ui::AX_STATE_VERTICAL))
     return NSAccessibilityVerticalOrientationValue;
   else if (GetState(browserAccessibility_, ui::AX_STATE_HORIZONTAL))
     return NSAccessibilityHorizontalOrientationValue;
 
   return @"";
 }
 
 - (NSNumber*)numberOfCharacters {
-  return [NSNumber numberWithInt:browserAccessibility_->value().length()];
+  std::string value = browserAccessibility_->GetStringAttribute(
+      ui::AX_ATTR_VALUE);
+  return [NSNumber numberWithInt:value.size()];
 }
 
 // The origin of this accessibility object in the page's document.
 // This is relative to webkit's top-left origin, not Cocoa's
 // bottom-left origin.
 - (NSPoint)origin {
   gfx::Rect bounds = browserAccessibility_->GetLocalBoundsRect();
   return NSMakePoint(bounds.x(), bounds.y());
 }
 
@@ skipping 415 matching lines @@
   return NSStringForStringAttribute(
       browserAccessibility_, ui::AX_ATTR_VALUE);
 }
 
 - (NSString*)valueDescription {
   return NSStringForStringAttribute(
       browserAccessibility_, ui::AX_ATTR_VALUE);
 }
 
 - (NSValue*)visibleCharacterRange {
-  return [NSValue valueWithRange:
-      NSMakeRange(0, browserAccessibility_->value().length())];
+  std::string value = browserAccessibility_->GetStringAttribute(
+      ui::AX_ATTR_VALUE);
+  return [NSValue valueWithRange:NSMakeRange(0, value.size())];
 }
 
 - (NSArray*)visibleCells {
   NSMutableArray* ret = [[[NSMutableArray alloc] init] autorelease];
   const std::vector<int32>& uniqueCellIds =
       browserAccessibility_->GetIntListAttribute(
           ui::AX_ATTR_UNIQUE_CELL_IDS);
   for (size_t i = 0; i < uniqueCellIds.size(); ++i) {
     int id = uniqueCellIds[i];
     BrowserAccessibility* cell =
@@ skipping 93 matching lines @@
 // Returns the accessibility value for the given attribute and parameter. If the
 // value isn't supported this will return nil.
 - (id)accessibilityAttributeValue:(NSString*)attribute
                      forParameter:(id)parameter {
   if (!browserAccessibility_)
     return nil;
 
   const std::vector<int32>& line_breaks =
       browserAccessibility_->GetIntListAttribute(
           ui::AX_ATTR_LINE_BREAKS);
-  int len = static_cast<int>(browserAccessibility_->value().size());
+  std::string value = browserAccessibility_->GetStringAttribute(
+      ui::AX_ATTR_VALUE);
+  int len = static_cast<int>(value.size());
 
   if ([attribute isEqualToString:
       NSAccessibilityStringForRangeParameterizedAttribute]) {
     NSRange range = [(NSValue*)parameter rangeValue];
     std::string value = browserAccessibility_->GetStringAttribute(
         ui::AX_ATTR_VALUE);
     return base::SysUTF8ToNSString(value.substr(range.location, range.length));
   }
 
   if ([attribute isEqualToString:
@@ skipping 513 matching lines @@
   if (!browserAccessibility_)
     return [super hash];
   return browserAccessibility_->GetId();
 }
 
 - (BOOL)accessibilityShouldUseUniqueId {
   return YES;
 }
 
 @end