Add multi_process_lock to chrome/common

chrome/common/multi_process_lock_mac.cc

Index: chrome/common/multi_process_lock_mac.cc
diff --git a/chrome/common/multi_process_lock_mac.cc b/chrome/common/multi_process_lock_mac.cc
new file mode 100644
index 0000000000000000000000000000000000000000..896e750fdcf693f7e6d4ec0e13f11d1750835b8e
--- /dev/null
+++ b/chrome/common/multi_process_lock_mac.cc
@@ -0,0 +1,35 @@
+// Copyright (c) 2010 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/common/multi_process_lock.h"
+
+#include "base/mac/scoped_cftyperef.h"
+#include "base/sys_string_conversions.h"
+
+class MultiProcessLockMac : public MultiProcessLock {
+ public:
+  explicit MultiProcessLockMac(const std::string& name)
+      : MultiProcessLock(name) { }
+
+  virtual ~MultiProcessLockMac() { Unlock(); }
+
+  virtual bool TryLock() {
+    CFStringRef cf_name(base::SysUTF8ToCFStringRef(name_));
+    base::mac::ScopedCFTypeRef<CFStringRef> scoped_cf_name(cf_name);
+    port_.reset(CFMessagePortCreateLocal(NULL, cf_name, NULL, NULL, NULL));
+    return port_ != NULL;
+  }
+
+  virtual void Unlock() {
+    port_.reset();
+  }
+
+ private:
+  base::mac::ScopedCFTypeRef<CFMessagePortRef> port_;
+  DISALLOW_COPY_AND_ASSIGN(MultiProcessLockMac);
+};
+
+MultiProcessLock* MultiProcessLock::Create(const std::string &name) {
+  return new MultiProcessLockMac(name);
+}