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

util/mac/service_management_test.mm

 // 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/mac/service_management.h"
 
 #import <Foundation/Foundation.h>
 #include <launch.h>
 
 #include <string>
 #include <vector>
 
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/sys_string_conversions.h"
-#include "base/rand_util.h"
 #include "gtest/gtest.h"
 #include "util/misc/clock.h"
+#include "util/misc/random_string.h"
 #include "util/posix/process_info.h"
 #include "util/stdlib/objc.h"
 
 namespace crashpad {
 namespace test {
 namespace {
 
 // Ensures that the process with the specified PID is running, identifying it by
 // requiring that its argv[argc - 1] compare equal to last_arg.
 void ExpectProcessIsRunning(pid_t pid, std::string& last_arg) {
@@ skipping 61 matching lines @@
       SleepNanoseconds(1E6);  // 1 millisecond
     }
   }
 
   ASSERT_FALSE(job_argv.empty());
   EXPECT_NE(last_arg, job_argv.back());
 }
 
 TEST(ServiceManagement, SubmitRemoveJob) {
   @autoreleasepool {
-    std::string cookie;
-    for (int index = 0; index < 16; ++index) {
-      cookie.append(1, base::RandInt('A', 'Z'));
-    }
+    const std::string cookie = RandomString();
 
     std::string shell_script =
         base::StringPrintf("sleep 10; echo %s", cookie.c_str());
     NSString* shell_script_ns = base::SysUTF8ToNSString(shell_script);
 
     const char kJobLabel[] = "org.chromium.crashpad.test.service_management";
     NSDictionary* job_dictionary_ns = @{
       @LAUNCH_JOBKEY_LABEL : @"org.chromium.crashpad.test.service_management",
       @LAUNCH_JOBKEY_RUNATLOAD : @YES,
       @LAUNCH_JOBKEY_PROGRAMARGUMENTS :
@@ skipping 29 matching lines @@
     // an error.
     EXPECT_FALSE(ServiceManagementRemoveJob(kJobLabel, false));
 
     ExpectProcessIsNotRunning(job_pid, shell_script);
   }
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad