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

test/scoped_temp_dir_win.cc

 // Copyright 2015 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 "test/scoped_temp_dir.h"
 
 #include <windows.h>
 
 #include "base/logging.h"
-#include "base/rand_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "util/misc/random_string.h"
 #include "gtest/gtest.h"
 
 namespace crashpad {
 namespace test {
 
 namespace {
 
 base::FilePath GenerateCandidateName() {
   wchar_t temp_path[MAX_PATH + 1];
   DWORD path_len = GetTempPath(MAX_PATH, temp_path);
   PCHECK(path_len != 0) << "GetTempPath";
   base::FilePath system_temp_dir(temp_path);
   base::string16 new_dir_name = base::UTF8ToUTF16(base::StringPrintf(
-        "crashpad.test.%d.%I64x", GetCurrentProcessId(), base::RandUint64()));
+        "crashpad.test.%d.%s", GetCurrentProcessId(), RandomString().c_str()));
   return system_temp_dir.Append(new_dir_name);
 }
 
 const int kRetries = 50;
 
 }  // namespace
 
 void ScopedTempDir::Rename() {
   for (int count = 0; count < kRetries; ++count) {
     // Try to move to a new temporary directory with a randomly generated name.
@@ skipping 47 matching lines @@
       EXPECT_TRUE(DeleteFile(entry_path.value().c_str()));
   } while (FindNextFile(search_handle, &find_data));
   EXPECT_EQ(ERROR_NO_MORE_FILES, GetLastError());
 
   EXPECT_TRUE(FindClose(search_handle));
   EXPECT_TRUE(RemoveDirectory(path.value().c_str()));
 }
 
 }  // namespace test
 }  // namespace crashpad