FilePath::Append() doesn't allow you to append a fully-qualified...

net/tools/dump_cache/cache_dumper.cc

Index: net/tools/dump_cache/cache_dumper.cc
===================================================================
--- net/tools/dump_cache/cache_dumper.cc	(revision 30060)
+++ net/tools/dump_cache/cache_dumper.cc	(working copy)
@@ -70,7 +70,11 @@
   // In order for long filenames to work, we'll need to prepend
   // the windows magic token.
   const std::wstring kLongFilenamePrefix(L"\\\\?\\");
-  entry_path_ = FilePath(kLongFilenamePrefix).Append(entry_path_);
+  // There is no way to prepend to a filename.  We simply *have*
+  // to convert to a wstring to do this.
+  std::wstring name = kLongFilenamePrefix;
+  name.append(entry_path_.ToWStringHack());
+  entry_path_ = FilePath(name);
 #endif
 
   entry_url_ = key;