Add AXTreeDelegate and refactor other AXTree classes slightly.

ui/accessibility/ax_tree_serializer_unittest.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 "base/memory/scoped_ptr.h"
 #include "base/strings/string_number_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/accessibility/ax_node.h"
 #include "ui/accessibility/ax_serializable_tree.h"
 #include "ui/accessibility/ax_tree.h"
@@ skipping 12 matching lines @@
   AXTreeSerializerTest() {}
   virtual ~AXTreeSerializerTest() {}
 
  protected:
   void CreateTreeSerializer();
 
   AXTreeUpdate treedata0_;
   AXTreeUpdate treedata1_;
   scoped_ptr<AXSerializableTree> tree0_;
   scoped_ptr<AXSerializableTree> tree1_;
-  scoped_ptr<AXTreeSource<AXNode> > tree0_source_;
-  scoped_ptr<AXTreeSource<AXNode> > tree1_source_;
-  scoped_ptr<AXTreeSerializer<AXNode> > serializer_;
+  scoped_ptr<AXTreeSource<const AXNode*> > tree0_source_;
+  scoped_ptr<AXTreeSource<const AXNode*> > tree1_source_;
+  scoped_ptr<AXTreeSerializer<const AXNode*> > serializer_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AXTreeSerializerTest);
 };
 
 void AXTreeSerializerTest::CreateTreeSerializer() {
   if (serializer_)
     return;
 
   tree0_.reset(new AXSerializableTree(treedata0_));
   tree1_.reset(new AXSerializableTree(treedata1_));
 
   // Serialize tree0 so that AXTreeSerializer thinks that its client
   // is totally in sync.
   tree0_source_.reset(tree0_->CreateTreeSource());
-  serializer_.reset(new AXTreeSerializer<AXNode>(tree0_source_.get()));
+  serializer_.reset(new AXTreeSerializer<const AXNode*>(tree0_source_.get()));
   AXTreeUpdate unused_update;
   serializer_->SerializeChanges(tree0_->GetRoot(), &unused_update);
 
   // Pretend that tree0_ turned into tree1_. The next call to
   // AXTreeSerializer will force it to consider these changes to
   // the tree and send them as part of the next update.
   tree1_source_.reset(tree1_->CreateTreeSource());
   serializer_->ChangeTreeSourceForTesting(tree1_source_.get());
 }
 
@@ skipping 111 matching lines @@
   // then include nodes 2...5.
   EXPECT_EQ(2, update.node_id_to_clear);
   ASSERT_EQ(static_cast<size_t>(4), update.nodes.size());
   EXPECT_EQ(2, update.nodes[0].id);
   EXPECT_EQ(3, update.nodes[1].id);
   EXPECT_EQ(4, update.nodes[2].id);
   EXPECT_EQ(5, update.nodes[3].id);
 }
 
 }  // namespace ui