Revert 176659

base/file_util_posix.cc

Index: base/file_util_posix.cc
===================================================================
--- base/file_util_posix.cc	(revision 176660)
+++ base/file_util_posix.cc	(working copy)
@@ -343,15 +343,15 @@
   DCHECK(recursive || S_ISDIR(info.stat.st_mode));
 
   while (success && !current.empty()) {
-    // current is the source path, including from_path, so append
-    // the suffix after from_path to to_path to create the target_path.
-    FilePath target_path(to_path);
-    if (from_path_base != current) {
-      if (!from_path_base.AppendRelativePath(current, &target_path)) {
-        success = false;
-        break;
-      }
+    // current is the source path, including from_path, so paste
+    // the suffix after from_path onto to_path to create the target_path.
+    std::string suffix(&current.value().c_str()[from_path_base.value().size()]);
+    // Strip the leading '/' (if any).
+    if (!suffix.empty()) {
+      DCHECK_EQ('/', suffix[0]);
+      suffix.erase(0, 1);
     }
+    const FilePath target_path = to_path.Append(suffix);
 
     if (S_ISDIR(info.stat.st_mode)) {
       if (mkdir(target_path.value().c_str(), info.stat.st_mode & 01777) != 0 &&