Update PDF accessibility when zoom level changes

content/renderer/accessibility/render_accessibility_impl.cc

 // 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 "content/renderer/accessibility/render_accessibility_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <queue>
@@ skipping 241 matching lines @@
 int RenderAccessibilityImpl::GenerateAXID() {
   WebAXObject root = tree_source_.GetRoot();
   return root.generateAXID();
 }
 
 void RenderAccessibilityImpl::SetPdfTreeSource(
     RenderAccessibilityImpl::PdfAXTreeSource* pdf_tree_source) {
   pdf_tree_source_ = pdf_tree_source;
   pdf_serializer_.reset(new PdfAXTreeSerializer(pdf_tree_source_));
 
+  OnPdfRootNodeUpdated();
+}
+
+void RenderAccessibilityImpl::OnPdfRootNodeUpdated() {
+  // Search the accessibility tree for an EMBED element and post a
+  // children changed notification on it to force it to update the
+  // PDF accessibility tree.
+
   ScopedFreezeBlinkAXTreeSource freeze(&tree_source_);
   WebAXObject root = tree_source_.GetRoot();
   if (!root.updateLayoutAndCheckValidity())
     return;
 
   std::queue<WebAXObject> objs_to_explore;
   objs_to_explore.push(root);
   while (objs_to_explore.size()) {
     WebAXObject obj = objs_to_explore.front();
     objs_to_explore.pop();
@@ skipping 442 matching lines @@
       size_t new_count = pdf_update.nodes.size();
       update->nodes.resize(old_count + new_count);
       for (size_t i = 0; i < new_count; ++i)
         update->nodes[old_count + i] = pdf_update.nodes[i];
       break;
     }
   }
 }
 
 }  // namespace content