Add the crashpad_handler executable

handler/mac/exception_handler_server.h

Index: handler/mac/exception_handler_server.h
diff --git a/handler/mac/exception_handler_server.h b/handler/mac/exception_handler_server.h
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+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CRASHPAD_HANDLER_MAC_EXCEPTION_HANDLER_SERVER_H_
+#define CRASHPAD_HANDLER_MAC_EXCEPTION_HANDLER_SERVER_H_
+
+#include "base/basictypes.h"
+
+#include <mach/mach.h>
+
+#include "base/mac/scoped_mach_port.h"
+
+namespace crashpad {
+
+//! \brief Runs the main exception-handling server in Crashpad’s handler
+//!     process.
+class ExceptionHandlerServer {
+ public:
+  ExceptionHandlerServer();
+  ~ExceptionHandlerServer();
+
+  //! \brief Runs the exception-handling server.
+  //!
+  //! This method monitors \a receive_port_ for exception messages and
+  //! no-senders notifications. It continues running until it has no more
+  //! clients, indicated by the receipt of a no-senders notification. It is
+  //! important to assure that a send right has been transferred to a client
+  //! (or queued by `mach_msg()` to be sent to a client) prior to calling this
+  //! method, or it will detect that it is sender-less and return immediately.
+  //!
+  //! This method must only be called once on an ExceptionHandlerServer object.
+  //!
+  //! If an unexpected condition that prevents this method from functioning is
+  //! encountered, it will log a message and terminate execution. Receipt of an
+  //! invalid message on \a receive_port_ will cause a message to be logged, but
+  //! this method will continue running normally.
+  void Run();
+
+  //! \brief Returns the receive right that will be monitored for exception
+  //!     messages.
+  //!
+  //! The caller does not take ownership of this port. The caller must not use
+  //! this port for any purpose other than to make send rights for clients.
+  mach_port_t receive_port() const { return receive_port_; }
+
+ private:
+  base::mac::ScopedMachReceiveRight receive_port_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExceptionHandlerServer);
+};
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_HANDLER_MAC_EXCEPTION_HANDLER_SERVER_H_