HTML Meter tag should have MSAA+IA2 as ROLE_SYSTEM_PROGRESSBAR.

ui/accessibility/platform/ax_platform_node_mac.mm

 // Copyright 2014 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 "ui/accessibility/platform/ax_platform_node_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/strings/sys_string_conversions.h"
 #import "ui/accessibility/platform/ax_platform_node_delegate.h"
@@ skipping 69 matching lines @@
       {ui::AX_ROLE_MATH, NSAccessibilityGroupRole},
       {ui::AX_ROLE_MATTE, NSAccessibilityMatteRole},
       {ui::AX_ROLE_MENU, NSAccessibilityMenuRole},
       {ui::AX_ROLE_MENU_BAR, NSAccessibilityMenuBarRole},
       {ui::AX_ROLE_MENU_BUTTON, NSAccessibilityButtonRole},
       {ui::AX_ROLE_MENU_ITEM, NSAccessibilityMenuItemRole},
       {ui::AX_ROLE_MENU_ITEM_CHECK_BOX, NSAccessibilityMenuItemRole},
       {ui::AX_ROLE_MENU_ITEM_RADIO, NSAccessibilityMenuItemRole},
       {ui::AX_ROLE_MENU_LIST_OPTION, NSAccessibilityMenuItemRole},
       {ui::AX_ROLE_MENU_LIST_POPUP, NSAccessibilityUnknownRole},
+      {ui::AX_ROLE_METER, NSAccessibilityProgressIndicatorRole},
       {ui::AX_ROLE_NAVIGATION, NSAccessibilityGroupRole},
       {ui::AX_ROLE_NONE, NSAccessibilityGroupRole},
       {ui::AX_ROLE_NOTE, NSAccessibilityGroupRole},
       {ui::AX_ROLE_OUTLINE, NSAccessibilityOutlineRole},
       {ui::AX_ROLE_PARAGRAPH, NSAccessibilityGroupRole},
       {ui::AX_ROLE_POP_UP_BUTTON, NSAccessibilityPopUpButtonRole},
       {ui::AX_ROLE_PRESENTATIONAL, NSAccessibilityGroupRole},
       {ui::AX_ROLE_PROGRESS_INDICATOR, NSAccessibilityProgressIndicatorRole},
       {ui::AX_ROLE_RADIO_BUTTON, NSAccessibilityRadioButtonRole},
       {ui::AX_ROLE_RADIO_GROUP, NSAccessibilityRadioGroupRole},
@@ skipping 209 matching lines @@
   delete this;
 }
 
 gfx::NativeViewAccessible AXPlatformNodeMac::GetNativeViewAccessible() {
   if (!native_node_)
     native_node_.reset([[AXPlatformNodeCocoa alloc] initWithNode:this]);
   return native_node_.get();
 }
 
 }  // namespace ui