Moving away from shell api to support long path names on windows for filesystem.

base/file_path.h

Index: base/file_path.h
===================================================================
--- base/file_path.h	(revision 69859)
+++ base/file_path.h	(working copy)
@@ -151,6 +151,16 @@
   // The character used to identify a file extension.
   static const CharType kExtensionSeparator;
 
+#if defined(OS_WIN)
+  // Path length is limited to 260 on Windows unless prefixed
+  // with a special extended path prefix. UNC needs a separate
+  // prefix containing "UNC" in it.
+  static const CharType kExtendedPathPrefix[];
+  static const CharType kUNCExtendedPathPrefix[];
+  // '\\' Prefix for network shares.

[Erik does not do reviews, 2010/12/23 17:57:27]

nit: newline above comments

+  static const CharType kSharePrefix[];
+#endif
+
   FilePath();
   FilePath(const FilePath& that);
   explicit FilePath(const StringType& path);
@@ -307,6 +317,18 @@
   FilePath NormalizeWindowsPathSeparators() const;
 #endif
 
+#if defined(OS_WIN)
+  // Gets the long form if it is in 8.3 file name format. Note that this
+  // is not supported for WinCE.
+  // This also prepends the extended path prefix so that paths longer
+  // than MAX_PATH char can be supported.
+  // Note: The path needs to exist to make this return a correct long path

[Erik does not do reviews, 2010/12/23 17:57:27]

This isn't acceptable in FilePath.  One of FilePath's invariants is that it's
supposed to never generate IO.  It should be safe to call FilePath methods from
any thread.  If we need to do this 8.3 shortname lookup, then we need to add it
to file_util instead.  Maybe that's OK since the only time we should be doing
this is inside of file_util already, right?

+  // if it has 8.3 short names contained in it.
+  FilePath GetLongPathHack() const;
+
+  bool StartsWithExtendedPathOrUNCPrefix() const;
+#endif
+
   // Compare two strings in the same way the file system does.
   // Note that these always ignore case, even on file systems that are case-
   // sensitive. If case-sensitive comparison is ever needed, add corresponding