Implement accessibility support for CSS-transformed iframes.

content/renderer/accessibility/blink_ax_tree_source.cc

 // 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.
 
 #include "content/renderer/accessibility/blink_ax_tree_source.h"
 
 #include <stddef.h>
 
 #include <set>
 
@@ skipping 499 matching lines @@
       dst->role == ui::AX_ROLE_SCROLL_BAR ||
       dst->role == ui::AX_ROLE_SLIDER ||
       dst->role == ui::AX_ROLE_SPIN_BUTTON) {
     dst->AddFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE, src.valueForRange());
     dst->AddFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE,
                            src.maxValueForRange());
     dst->AddFloatAttribute(ui::AX_ATTR_MIN_VALUE_FOR_RANGE,
                            src.minValueForRange());
   }
 
-  if (dst->role == ui::AX_ROLE_WEB_AREA)
+  if (dst->role == ui::AX_ROLE_WEB_AREA) {
     dst->AddStringAttribute(ui::AX_ATTR_HTML_TAG, "#document");
+    dst->transform = gfx::Transform(src.localFrameRootTransform());
+  }
 
   if (dst->role == ui::AX_ROLE_TABLE) {
     int column_count = src.columnCount();
     int row_count = src.rowCount();
     if (column_count > 0 && row_count > 0) {
       std::set<int32_t> unique_cell_id_set;
       std::vector<int32_t> cell_ids;
       std::vector<int32_t> unique_cell_ids;
       dst->AddIntAttribute(ui::AX_ATTR_TABLE_COLUMN_COUNT, column_count);
       dst->AddIntAttribute(ui::AX_ATTR_TABLE_ROW_COUNT, row_count);
@@ skipping 89 matching lines @@
   }
 }
 
 blink::WebDocument BlinkAXTreeSource::GetMainDocument() const {
   if (render_frame_ && render_frame_->GetWebFrame())
     return render_frame_->GetWebFrame()->document();
   return WebDocument();
 }
 
 }  // namespace content