Refactor and send voice interaction structure

content/browser/web_contents/web_contents_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/browser/web_contents/web_contents_impl.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <utility>
@@ skipping 956 matching lines @@
       UpdateAccessibilityModeOnFrame(pending_frame_host);
   }
 }
 
 void WebContentsImpl::AddAccessibilityMode(AccessibilityMode mode) {
   AccessibilityMode new_mode(accessibility_mode_);
   new_mode |= mode;
   SetAccessibilityMode(new_mode);
 }
 
-void WebContentsImpl::RequestAXTreeSnapshot(AXTreeSnapshotCallback callback) {
+void WebContentsImpl::RequestAXTreeSnapshot(
+    const AXTreeSnapshotCallback& callback) {
   // Send a request to each of the frames in parallel. Each one will return
   // an accessibility tree snapshot, and AXTreeSnapshotCombiner will combine
   // them into a single tree and call |callback| with that result, then
   // delete |combiner|.
   AXTreeSnapshotCombiner* combiner = new AXTreeSnapshotCombiner(callback);
   for (FrameTreeNode* frame_tree_node : frame_tree_.Nodes()) {
     bool is_root = frame_tree_node->parent() == nullptr;
     frame_tree_node->current_frame_host()->RequestAXTreeSnapshot(
         combiner->AddFrame(is_root));
   }
@@ skipping 4484 matching lines @@
     RenderViewHost* render_view_host = RenderViewHost::From(render_widget_host);
     if (!render_view_host)
       continue;
     render_view_host_set.insert(render_view_host);
   }
   for (RenderViewHost* render_view_host : render_view_host_set)
     render_view_host->OnWebkitPreferencesChanged();
 }
 
 }  // namespace content