Improve formatting of accessibility tests that dump the tree.

content/browser/accessibility/dump_accessibility_tree_helper.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_DUMP_ACCESSIBILITY_TREE_HELPER_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_DUMP_ACCESSIBILITY_TREE_HELPER_H_
 
 #include "base/file_path.h"
 #include "base/string16.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/accessibility/browser_accessibility.h"
 
 // A utility class for retrieving platform specific accessibility information.
+// This is extended by a subclass for each platform where accessibility is
+// implemented.
 class DumpAccessibilityTreeHelper {
  public:
   // Dumps a BrowserAccessibility tree into a string.
   void DumpAccessibilityTree(BrowserAccessibility* node,
-                             string16* contents) {
-    *contents += ToString(node) + GetLineEnding();
-    for (size_t i = 0; i < node->children().size(); ++i)
-      DumpAccessibilityTree(node->children()[i], contents);
-  }
+                             string16* contents);
 
   // Suffix of the expectation file corresponding to html file.
   // Example:
   // HTML test:      test-file.html
   // Expected:       test-file-expected-mac.txt.
   // Auto-generated: test-file-actual-mac.txt
   const FilePath::StringType GetActualFileSuffix() const;
   const FilePath::StringType GetExpectedFileSuffix() const;
 
-  // Line ending to use in our dump.
-  const string16 GetLineEnding() const;
+ protected:
+  void RecursiveDumpAccessibilityTree(BrowserAccessibility* node,
+                                      string16* contents,
+                                      int indent);
 
- protected:
   // Returns a platform specific representation of a BrowserAccessibility.
-  string16 ToString(BrowserAccessibility* node);
+  // Should be zero or more complete lines, each with |prefix| prepended
+  // (to indent each line).
+  string16 ToString(BrowserAccessibility* node, char* prefix);
 
   void Initialize();
 };
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_DUMP_ACCESSIBILITY_TREE_HELPER_H_