Fix filesystem API file_handlers to work for drive on ChromeOS.

webkit/fileapi/isolated_context.cc

Index: webkit/fileapi/isolated_context.cc
diff --git a/webkit/fileapi/isolated_context.cc b/webkit/fileapi/isolated_context.cc
index 56ba1c00dfa50150d9d453195283a124817dc943..e97f86ebebc09a8d11aa247b42bfbd8a1c5ef3d0 100644
--- a/webkit/fileapi/isolated_context.cc
+++ b/webkit/fileapi/isolated_context.cc
@@ -323,6 +323,11 @@ FileSystemURL IsolatedContext::CreateCrackedFileSystemURL(
                        mount_name, cracked_type, cracked_path);
 }
 
+bool IsolatedContext::GetVirtualPath(const base::FilePath& full_path,
+                                     base::FilePath* virtual_path) const {
+  return false;
+}
+
 void IsolatedContext::RevokeFileSystemByPath(const base::FilePath& path_in) {
   base::AutoLock locker(lock_);
   base::FilePath path(path_in.NormalizePathSeparators());