PNaCl on-demand installs: Make a separate async IPC to check if PNaCl is installed

components/nacl/common/pnacl_types.cc

 // Copyright 2013 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 "components/nacl/common/pnacl_types.h"
 
 namespace nacl {
 
 PnaclCacheInfo::PnaclCacheInfo() {}
 PnaclCacheInfo::~PnaclCacheInfo() {}
 
+// static
+bool PnaclInstallProgress::progress_known(const PnaclInstallProgress& p) {
+  return p.total_size >= 0;
+}
+
+// static
+PnaclInstallProgress PnaclInstallProgress::Unknown() {
+  PnaclInstallProgress p;
+  p.current = 0;
+  // Use -1 to indicate that total is not determined.
+  // This matches the -1 of the OnURLFetchDownloadProgress interface in
+  // net/url_request/url_fetcher_delegate.h
+  p.total_size = -1;
+  return p;
+}
+
 }  // namespace nacl