Revert 113027 - Zygote most of the uses of the utility process on Linux

chrome/browser/extensions/sandboxed_extension_unpacker.cc

Index: chrome/browser/extensions/sandboxed_extension_unpacker.cc
===================================================================
--- chrome/browser/extensions/sandboxed_extension_unpacker.cc	(revision 113164)
+++ chrome/browser/extensions/sandboxed_extension_unpacker.cc	(working copy)
@@ -261,9 +261,6 @@
 void SandboxedExtensionUnpacker::StartProcessOnIOThread(
     const FilePath& temp_crx_path) {
   UtilityProcessHost* host = new UtilityProcessHost(this, thread_identifier_);
-  // Don't launch the utility process from the zygote on Linux since
-  // extension unpacking needs FS access.
-  host->set_use_linux_zygote(false);
   // Grant the subprocess access to the entire subdir the extension file is
   // in, so that it can unpack to that dir.
   host->set_exposed_dir(temp_crx_path.DirName());