One accessibility tree per frame.

content/browser/accessibility/browser_accessibility_android.cc

 // Copyright 2013 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 "content/browser/accessibility/browser_accessibility_android.h"
 
 #include "base/i18n/break_iterator.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
@@ skipping 284 matching lines @@
       class_name = "android.widget.GridView";
       break;
     case ui::AX_ROLE_LIST:
     case ui::AX_ROLE_LIST_BOX:
     case ui::AX_ROLE_DESCRIPTION_LIST:
       class_name = "android.widget.ListView";
       break;
     case ui::AX_ROLE_DIALOG:
       class_name = "android.app.Dialog";
       break;
     case ui::AX_ROLE_ROOT_WEB_AREA:

[David Tseng, 2016/03/04 16:50:20]

So, AX_ROLE_WEB_AREA is no longer used?

[dmazzoni, 2016/03/07 21:35:32]

Yes. I was planning to delete it in a follow-up change, but that would touch a
lot of files so I didn't want to do it here.

-      class_name = "android.webkit.WebView";
+      if (GetParent() == nullptr)
+        class_name = "android.webkit.WebView";
+      else
+        class_name = "android.view.View";
       break;
     case ui::AX_ROLE_MENU_ITEM:
     case ui::AX_ROLE_MENU_ITEM_CHECK_BOX:
     case ui::AX_ROLE_MENU_ITEM_RADIO:
       class_name = "android.view.MenuItem";
       break;
     default:
       class_name = "android.view.View";
       break;
   }
@@ skipping 611 matching lines @@
   int x = GetIntAttribute(ui::AX_ATTR_SCROLL_X);
   int x_min = GetIntAttribute(ui::AX_ATTR_SCROLL_X_MIN);
   int x_max = GetIntAttribute(ui::AX_ATTR_SCROLL_X_MAX);
   int y = GetIntAttribute(ui::AX_ATTR_SCROLL_Y);
   int y_min = GetIntAttribute(ui::AX_ATTR_SCROLL_Y_MIN);
   int y_max = GetIntAttribute(ui::AX_ATTR_SCROLL_Y_MAX);
 
   // Figure out the bounding box of the visible portion of this scrollable
   // view so we know how much to scroll by.
   gfx::Rect bounds;
-  if (GetRole() == ui::AX_ROLE_ROOT_WEB_AREA) {
+  if (GetRole() == ui::AX_ROLE_ROOT_WEB_AREA && !GetParent()) {
     // If this is the root web area, use the bounds of the view to determine
     // how big one page is.
     if (!manager()->delegate())
       return false;
     bounds = manager()->delegate()->AccessibilityGetViewBounds();
-  } else if (GetRole() == ui::AX_ROLE_WEB_AREA) {
+  } else if (GetRole() == ui::AX_ROLE_ROOT_WEB_AREA) {

[David Tseng, 2016/03/04 16:50:20]

&& GetParent()

[dmazzoni, 2016/03/07 21:35:32]

Done.

     // If this is a web area inside of an iframe, try to use the bounds of
     // the containing element.
     BrowserAccessibility* parent = GetParent();
     while (parent && (parent->GetLocation().width() == 0 ||
                       parent->GetLocation().height() == 0)) {
       parent = parent->GetParent();
     }
     if (parent)
       bounds = parent->GetLocation();
     else
@@ skipping 424 matching lines @@
 int BrowserAccessibilityAndroid::CountChildrenWithRole(ui::AXRole role) const {
   int count = 0;
   for (uint32_t i = 0; i < PlatformChildCount(); i++) {
     if (PlatformGetChild(i)->GetRole() == role)
       count++;
   }
   return count;
 }
 
 }  // namespace content