Modify AccessibilityTreeFormatter to build up an internal representation of the tree

content/browser/accessibility/accessibility_tree_formatter.h

 // 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.
 
 #ifndef CONTENT_BROWSER_ACCESSIBILITY_ACCESSIBILITY_TREE_FORMATTER_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_ACCESSIBILITY_TREE_FORMATTER_H_
 
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/string16.h"
 #include "base/utf_string_conversions.h"
+#include "base/values.h"
 #include "content/browser/accessibility/browser_accessibility.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 class RenderViewHost;
 
 // A utility class for formatting platform-specific accessibility information,
 // for use in testing, debugging, and developer tools.
 // This is extended by a subclass for each platform where accessibility is
 // implemented.
 class CONTENT_EXPORT AccessibilityTreeFormatter {
  public:
-  explicit AccessibilityTreeFormatter(BrowserAccessibility* node);
+  explicit AccessibilityTreeFormatter(BrowserAccessibility* root);
   virtual ~AccessibilityTreeFormatter();
 
   static AccessibilityTreeFormatter* Create(RenderViewHost* rvh);
 
+  // Populates the given DictionaryValue with the accessibility tree.

[dmazzoni, 2013/04/08 05:46:35]

Can you document the JSON schema here, or point to where it's documented or
defined?

A minimally complete and self-explanatory example JSON output would be more than
enough, I don't need paragraphs.

[aboxhall, 2013/04/10 03:09:34]

Done.

+  void BuildAccessibilityTree(DictionaryValue* dict);
+
   // Dumps a BrowserAccessibility tree into a string.
   void FormatAccessibilityTree(string16* contents);
 
+  // Overridden by each platform to add the required attributes for each node
+  // into the given dict.
+  void AddProperties(BrowserAccessibility* node, DictionaryValue* dict);

[dmazzoni, 2013/04/08 05:46:35]

Try making the first argument const to better distinguish it from the second
output argument.

I think this can be under "protected" - it doesn't need to be public, right?

[aboxhall, 2013/04/10 03:09:34]

Unfortunately ToBrowserAccessibilityCocoa() (and presumably
ToBrowserAccessibilityWin()) is non-const. I guess I could sneakily const_cast
it for that one method call, though.
Done.

+
   // A single filter specification. See GetAllowString() and GetDenyString()
   // for more information.
   struct Filter {
     enum Type {
       ALLOW,
       ALLOW_EMPTY,
       DENY
     };
     string16 match_str;
     Type type;
@@ skipping 28 matching lines @@
   // -->
   // <p>Text</p>
   static const std::string GetAllowEmptyString();
   static const std::string GetAllowString();
   static const std::string GetDenyString();
 
  protected:
   void RecursiveFormatAccessibilityTree(BrowserAccessibility* node,
                                         string16* contents,
                                         int indent);
+  void RecursiveBuildAccessibilityTree(BrowserAccessibility* node,
+                                       DictionaryValue* tree_node);
+  void RecursiveFormatAccessibilityTree(DictionaryValue* tree_node,
+                                        string16* contents,
+                                        int depth = 0);
 
   // Returns a platform specific representation of a BrowserAccessibility.
   // Should be zero or more complete lines, each with |prefix| prepended
   // (to indent each line).
-  string16 ToString(BrowserAccessibility* node, char* prefix);
+  string16 ToString(DictionaryValue* node, const string16& indent);
 
   void Initialize();
 
   bool MatchesFilters(const string16& text, bool default_result) const;
-  void StartLine();
-  void Add(bool include_by_default, const string16& attr);
-  string16 FinishLine();
 
-  BrowserAccessibility* node_;
+  // Writes the given attribute string out to |line| if it matches the filters.
+  void WriteAttribute(bool include_by_default,
+                      const string16& attr,
+                      string16* line);
+
+  BrowserAccessibility* root_;
+
+  // Filters used when formatting the accessibility tree as text.
   std::vector<Filter> filters_;
-  string16 line_;
 
   DISALLOW_COPY_AND_ASSIGN(AccessibilityTreeFormatter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_ACCESSIBILITY_TREE_FORMATTER_H_