Add RandomString() and its test, and use it everywhere it makes sense

util/mach/child_port_handshake.cc

 // 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,
@@ skipping 19 matching lines @@
 #include "base/posix/eintr_wrapper.h"
 #include "base/rand_util.h"
 #include "base/strings/stringprintf.h"
 #include "util/file/file_io.h"
 #include "util/mach/child_port.h"
 #include "util/mach/child_port_server.h"
 #include "util/mach/mach_extensions.h"
 #include "util/mach/mach_message.h"
 #include "util/mach/mach_message_server.h"
 #include "util/misc/implicit_cast.h"
+#include "util/misc/random_string.h"
 
 namespace crashpad {
 namespace {
 
 class ChildPortHandshakeServer final : public ChildPortServer::Interface {
  public:
   ChildPortHandshakeServer();
   ~ChildPortHandshakeServer();
 
   mach_port_t RunServer(base::ScopedFD server_write_fd,
@@ skipping 40 matching lines @@
     return MACH_PORT_NULL;
   }
 
   // Create a unique name for the bootstrap service mapping. Make it unguessable
   // to prevent outsiders from grabbing the name first, which would cause
   // bootstrap_check_in() to fail.
   uint64_t thread_id;
   errno = pthread_threadid_np(pthread_self(), &thread_id);
   PCHECK(errno == 0) << "pthread_threadid_np";
   std::string service_name = base::StringPrintf(
-      "org.chromium.crashpad.child_port_handshake.%d.%llu.%016llx",
+      "org.chromium.crashpad.child_port_handshake.%d.%llu.%s",
       getpid(),
       thread_id,
-      base::RandUint64());
+      RandomString().c_str());
 
   // Check the new service in with the bootstrap server, obtaining a receive
   // right for it.
   base::mac::ScopedMachReceiveRight server_port(BootstrapCheckIn(service_name));
   CHECK(server_port.is_valid());
 
   // Share the service name with the client via the pipe.
   uint32_t service_name_length = service_name.size();
   if (!LoggingWriteFile(server_write_fd.get(),
                         &service_name_length,
@@ skipping 325 matching lines @@
       server_port.get(), token, port, right_type);
   if (kr != KERN_SUCCESS) {
     MACH_LOG(ERROR, kr) << "child_port_check_in";
     return false;
   }
 
   return true;
 }
 
 }  // namespace crashpad