Stop returning the true root path of each filesystem from openFileSystem....

base/platform_file.h

Index: base/platform_file.h
===================================================================
--- base/platform_file.h	(revision 79142)
+++ base/platform_file.h	(working copy)
@@ -8,6 +8,7 @@
 
 #include "base/basictypes.h"
 #include "build/build_config.h"
+#include "base/file_path.h"
 #include "base/time.h"
 #if defined(OS_WIN)
 #include <windows.h>
@@ -15,8 +16,6 @@
 
 #include <string>
 
-class FilePath;
-
 namespace base {
 
 #if defined(OS_WIN)
@@ -91,6 +90,10 @@
 
   // The creation time of a file.
   base::Time creation_time;
+
+  // The full path of a file.  Currently only used by FileSystemFileUtil during
+  // a GetMetadata operation.
+  FilePath path;
 };
 
 // Creates or opens the given file. If PLATFORM_FILE_OPEN_ALWAYS is used, and