Add MinidumpSimpleStringDictionaryWriter and its test

minidump/minidump_string_writer_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,
@@ skipping 163 matching lines @@
       {8, "o\303\263\303\266\305\221o"},
       {4, "\360\220\204\202"},  // 𐄂 (non-BMP)
   };
 
   for (size_t index = 0; index < arraysize(kTestData); ++index) {
     SCOPED_TRACE(base::StringPrintf(
         "index %zu, input %s", index, kTestData[index].string));
 
     file_writer.Reset();
     crashpad::internal::MinidumpUTF8StringWriter string_writer;
-    string_writer.SetUTF8(
-        std::string(kTestData[index].string, kTestData[index].length));
+    std::string test_string(kTestData[index].string, kTestData[index].length);
+    string_writer.SetUTF8(test_string);
+    EXPECT_EQ(test_string, string_writer.UTF8());
     EXPECT_TRUE(string_writer.WriteEverything(&file_writer));
 
     const size_t expected_utf8_bytes_with_nul = kTestData[index].length + 1;
     ASSERT_EQ(sizeof(MinidumpUTF8String) + expected_utf8_bytes_with_nul,
               file_writer.string().size());
     const MinidumpUTF8String* minidump_string =
         MinidumpUTF8StringCast(file_writer);
     EXPECT_EQ(kTestData[index].length, minidump_string->Length);
     EXPECT_EQ(0,
               memcmp(kTestData[index].string,
                      minidump_string->Buffer,
                      expected_utf8_bytes_with_nul));
   }
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad