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

util/mach/mach_extensions_test.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,
 // 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.
 
 #include "util/mach/mach_extensions.h"
 
 #include "base/mac/scoped_mach_port.h"
-#include "base/rand_util.h"
 #include "gtest/gtest.h"
 #include "test/mac/mach_errors.h"
 #include "util/mac/mac_util.h"
+#include "util/misc/random_string.h"
 
 namespace crashpad {
 namespace test {
 namespace {
 
 TEST(MachExtensions, MachThreadSelf) {
   base::mac::ScopedMachSendRight thread_self(mach_thread_self());
   EXPECT_EQ(thread_self, MachThreadSelf());
 }
 
@@ skipping 100 matching lines @@
   EXPECT_TRUE(ExcMaskValid() & ~ExcMaskAll());
 }
 
 TEST(MachExtensions, BootstrapCheckInAndLookUp) {
   // This should always exist.
   base::mac::ScopedMachSendRight
       report_crash(BootstrapLookUp("com.apple.ReportCrash"));
   EXPECT_NE(report_crash, kMachPortNull);
 
   std::string service_name = "org.chromium.crashpad.test.bootstrap_check_in.";
-  for (int index = 0; index < 16; ++index) {
-    service_name.append(1, base::RandInt('A', 'Z'));
-  }
+  service_name.append(RandomString());
 
   {
     // The new service hasn’t checked in yet, so this should fail.
     base::mac::ScopedMachSendRight send(BootstrapLookUp(service_name));
     EXPECT_EQ(kMachPortNull, send);
 
     // Check it in.
     base::mac::ScopedMachReceiveRight receive(BootstrapCheckIn(service_name));
     EXPECT_NE(receive, kMachPortNull);
 
@@ skipping 17 matching lines @@
 
 TEST(MachExtensions, SystemCrashReporterHandler) {
   base::mac::ScopedMachSendRight
       system_crash_reporter_handler(SystemCrashReporterHandler());
   EXPECT_TRUE(system_crash_reporter_handler.is_valid());
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad