Convert calls to the utility process in extension code to use the zygote on Linux.

chrome/browser/extensions/webstore_install_helper.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/webstore_install_helper.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/values.h"
@@ skipping 50 matching lines @@
     url_fetcher_->SetRequestContext(context_getter_);
 
     url_fetcher_->Start();
     // We'll get called back in OnURLFetchComplete.
   }
 }
 
 void WebstoreInstallHelper::StartWorkOnIOThread() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   utility_host_ = new UtilityProcessHost(this, BrowserThread::IO);
+  utility_host_->set_use_linux_zygote(true);
   utility_host_->StartBatchMode();
 
   if (!icon_base64_data_.empty())
     utility_host_->Send(
         new ChromeUtilityMsg_DecodeImageBase64(icon_base64_data_));
 
   utility_host_->Send(new ChromeUtilityMsg_ParseJSON(manifest_));
 }
 
 void WebstoreInstallHelper::OnURLFetchComplete(
@@ skipping 99 matching lines @@
       base::Bind(&WebstoreInstallHelper::ReportResultFromUIThread, this));
 }
 
 void WebstoreInstallHelper::ReportResultFromUIThread() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (error_.empty() && parsed_manifest_.get())
     delegate_->OnWebstoreParseSuccess(id_, icon_, parsed_manifest_.release());
   else
     delegate_->OnWebstoreParseFailure(id_, parse_error_, error_);
 }