Move common file path related methods between chrome & content to file_util. I reduced the 4 meth...

base/file_util.h

Index: base/file_util.h
===================================================================
--- base/file_util.h	(revision 119906)
+++ base/file_util.h	(working copy)
@@ -388,6 +388,13 @@
 // Sets the current working directory for the process.
 BASE_EXPORT bool SetCurrentDirectory(const FilePath& path);
 
+// Attempts to find a number that can be appended to the |path| to make it
+// unique. If |path| does not exist, 0 is returned.  If it fails to find such
+// a number, -1 is returned. If |suffix| is not empty, also checks the
+// existence of it with the given suffix.
+BASE_EXPORT int GetUniquePathNumber(const FilePath& path,
+                                    const FilePath::StringType& suffix);
+
 #if defined(OS_POSIX)
 // Test that |path| can only be changed by a given user and members of
 // a given set of groups.