Don't require expectations file for DumpAccessibility tests.

content/browser/accessibility/accessibility_tree_formatter.cc

Index: content/browser/accessibility/accessibility_tree_formatter.cc
diff --git a/content/browser/accessibility/accessibility_tree_formatter.cc b/content/browser/accessibility/accessibility_tree_formatter.cc
index a60db9ad07c07139b18da071214296f22073c58c..14e672da151b509ab3b78c24c053ae839c4bbf4d 100644
--- a/content/browser/accessibility/accessibility_tree_formatter.cc
+++ b/content/browser/accessibility/accessibility_tree_formatter.cc
@@ -115,12 +115,6 @@ void AccessibilityTreeFormatter::Initialize() {}
 
 // static
 const base::FilePath::StringType
-AccessibilityTreeFormatter::GetActualFileSuffix() {
-  return base::FilePath::StringType();
-}
-
-// static
-const base::FilePath::StringType
 AccessibilityTreeFormatter::GetExpectedFileSuffix() {
   return base::FilePath::StringType();
 }