Add SimpleCache index file heuristics

net/disk_cache/simple/simple_index_file.h

Index: net/disk_cache/simple/simple_index_file.h
diff --git a/net/disk_cache/simple/simple_index_file.h b/net/disk_cache/simple/simple_index_file.h
index 00141634376e3fd3ef1df66c5033f3ba255473ff..882e8e5a95eef04002e941e620602363cce93d83 100644
--- a/net/disk_cache/simple/simple_index_file.h
+++ b/net/disk_cache/simple/simple_index_file.h
@@ -68,6 +68,10 @@ class NET_EXPORT_PRIVATE SimpleIndexFile {
   static void WriteToDisk(const base::FilePath& index_filename,
                           const Pickle& pickle);
 
+  // Using mtime of the file and the path, it detects if the index file is
+  // stale.
+  static bool IndexFileIsStale(const base::FilePath& index_filename);

[gavinp, 2013/04/19 09:30:17]

IsIndexFileStale is a better name. I did a double take when I first saw this.

[felipeg, 2013/04/19 10:14:05]

that comes from my bad english mixed up with french and portuguese

+
  private:
   FRIEND_TEST_ALL_PREFIXES(SimpleIndexFileTest, Serialize);